@article{PhysRevMaterials.8.104004,

title = {Uncovering hidden Fermi surface instabilities through visualizing unconventional quasiparticle interference in $mathrmCeTe_3$},

author = {B. R. M. Smith and Y. Fujisawa and P. Wu and T. Nakamura and N. Tomoda and S. Kuniyoshi and D. Ueta and R. Kobayashi and R. Okuma and K. Arai and K. Kuroda and C. -H. Hsu and G. Chang and C. -Y. Huang and H. Lin and Z. Y. Wang and T. Kondo and Y. Okada},

url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.8.104004},

doi = {10.1103/PhysRevMaterials.8.104004},

year  = {2024},

date = {2024-10-01},

journal = {Phys. Rev. Mater.},

volume = {8},

pages = {104004},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Iwasawa2024,

title = {Efficiency improvement of spin-resolved ARPES experiments using Gaussian process regression},

author = {Hideaki Iwasawa and Tetsuro Ueno and Takuma Iwata and Kenta Kuroda and Konstantin A. Kokh and Oleg E. Tereshchenko and Koji Miyamoto and Akio Kimura and Taichi Okuda},

url = {https://doi.org/10.1038/s41598-024-66704-8},

doi = {10.1038/s41598-024-66704-8},

year  = {2024},

date = {2024-09-23},

journal = {Scientific Reports},

volume = {14},

pages = {20970},

abstract = {The experimental efficiency has been a central concern for time-consuming experiments. Spin- and angle-resolved photoemission spectroscopy (spin-resolved ARPES) is renowned for its inefficiency in spin-detection, despite its outstanding capability to directly determine the spin-polarized electronic properties of materials. Here, we investigate the potential enhancement of the efficiency of spin-resolved ARPES experiments through the integration of measurement informatics. We focus on a representative topological insulator $$backslashtext Bi_2$$$$backslashtext Te_3$$, which has well-understood spin-polarized electronic states. We employ Gaussian process regression (GPR) to assess the accumulation of spin polarization information using an indicator known as the GPR score. Our analyses based on the GPR model suggest that the GPR score can serve as a stopping criterion for spin-resolved ARPES experiments. This criterion enables us to conduct efficient spin-resolved ARPES experiments, significantly reducing the time costs by 5-10 times, compared to empirical stopping criteria.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.133.086602,

title = {Robust Weak Topological Insulator in the Bismuth Halide Bi4Br2I2},

author = {Ryo Noguchi and Masaru Kobayashi and Kaishu Kawaguchi and Wataru Yamamori and Kohei Aido and Chun Lin and Hiroaki Tanaka and Kenta Kuroda and Ayumi Harasawa and Viktor Kandyba and Mattia Cattelan and Alexei Barinov and Makoto Hashimoto and Donghui Lu and Masayuki Ochi and Takao Sasagawa and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.133.086602},

doi = {10.1103/PhysRevLett.133.086602},

year  = {2024},

date = {2024-08-01},

urldate = {2024-08-01},

journal = {Phys. Rev. Lett.},

volume = {133},

pages = {086602},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.110.L041401,

title = {Spin-polarized saddle points in the topological surface states of elemental bismuth revealed by pump-probe spin- and angle-resolved photoemission spectroscopy},

author = {Yuto Fukushima and Kaishu Kawaguchi and Kenta Kuroda and Masayuki Ochi and Motoaki Hirayama and Ryo Mori and Hiroaki Tanaka and Ayumi Harasawa and Takushi Iimori and Zhigang Zhao and Shuntaro Tani and Koichiro Yaji and Shik Shin and Fumio Komori and Yohei Kobayashi and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevB.110.L041401},

doi = {10.1103/PhysRevB.110.L041401},

year  = {2024},

date = {2024-07-01},

journal = {Phys. Rev. B},

volume = {110},

pages = {L041401},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.133.016401,

title = {Fermi Surface Nesting Driving the RKKY Interaction in the Centrosymmetric Skyrmion Magnet Gd2PdSi3},

author = {Yuyang Dong and Yosuke Arai and Kenta Kuroda and Masayuki Ochi and Natsumi Tanaka and Yuxuan Wan and Matthew D. Watson and Timur K. Kim and Cephise Cacho and Makoto Hashimoto and Donghui Lu and Yuji Aoki and Tatsuma D. Matsuda and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.133.016401},

doi = {10.1103/PhysRevLett.133.016401},

year  = {2024},

date = {2024-07-01},

urldate = {2024-07-01},

journal = {Phys. Rev. Lett.},

volume = {133},

pages = {016401},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.109.L241114,

title = {Photoemission angular distribution beyond the single wavevector description of photoelectron final states},

author = {Hiroaki Tanaka and Shota Okazaki and Yuto Fukushima and Kaishu Kawaguchi and Ayumi Harasawa and Takushi Iimori and Fumio Komori and Masashi Arita and Ryo Mori and Kenta Kuroda and Takao Sasagawa and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevB.109.L241114 abst =We develop a simulation procedure for angle-resolved photoemission spectroscopy (ARPES), where a photoelectron wave function is set to be an outgoing plane wave in a vacuum associated with the emitted photoelectron wave packet. ARPES measurements on the transition metal dichalcogenide 1⁢𝑇−Ti⁢S2 are performed, and our simulations exhibit good agreement with experiments. Analysis of our calculated final state wave functions quantitatively visualizes that they include various waves due to the boundary condition and the uneven crystal potential. These results show that a more detailed investigation of the photoelectron final states is necessary to fully explain the photon-energy- and light-polarization-dependent ARPES spectra.},

doi = {10.1103/PhysRevB.109.L241114},

year  = {2024},

date = {2024-06-01},

journal = {Phys. Rev. B},

volume = {109},

pages = {L241114},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.132.136402,

title = {Broken Screw Rotational Symmetry in the Near-Surface Electronic Structure of $AB$-Stacked Crystals},

author = {Hiroaki Tanaka and Shota Okazaki and Masaru Kobayashi and Yuto Fukushima and Yosuke Arai and Takushi Iimori and Mikk Lippmaa and Kohei Yamagami and Yoshinori Kotani and Fumio Komori and Kenta Kuroda and Takao Sasagawa and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.132.136402},

doi = {10.1103/PhysRevLett.132.136402},

year  = {2024},

date = {2024-03-01},

urldate = {2024-03-01},

journal = {Phys. Rev. Lett.},

volume = {132},

pages = {136402},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Itaya2024,

title = {Substrate-Dependent Physical Properties at the Interface of Manganese(II) Phthalocyanine and Topological Insulators},

author = {Ryota Itaya and Yuki Higuchi and Tomoki Nishioka and Mito Tomita and Kenta Kuroda and Jun Fujii and Hitoshi Sato and Kazuyuki Sakamoto},

url = {https://doi.org/10.1021/acs.jpcc.3c07955},

doi = {10.1021/acs.jpcc.3c07955},

year  = {2024},

date = {2024-02-15},

journal = {The Journal of Physical Chemistry C},

volume = {128},

pages = {2705-2712},

publisher = {American Chemical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Iwata2024,

title = {Laser-based angle-resolved photoemission spectroscopy with micrometer spatial resolution and detection of three-dimensional spin vector},

author = {Takuma Iwata and T. Kousa and Y. Nishioka and K. Ohwada and K. Sumida and E. Annese and M. Kakoki and Kenta Kuroda and H. Iwasawa and M. Arita and S. Kumar and A. Kimura and K. Miyamoto and T. Okuda},

url = {https://doi.org/10.1038/s41598-023-47719-z},

doi = {10.1038/s41598-023-47719-z},

year  = {2024},

date = {2024-01-04},

urldate = {2024-01-04},

journal = {Scientific Reports},

volume = {14},

pages = {127},

abstract = {We have developed a state-of-the-art apparatus for laser-based spin- and angle-resolved photoemission spectroscopy with micrometer spatial resolution (textmu-SARPES). This equipment is realized by the combination of a high-resolution photoelectron spectrometer, a 6 eV laser with high photon flux that is focused down to a few micrometers, a high-precision sample stage control system, and a double very-low-energy-electron-diffraction spin detector. The setup achieves an energy resolution of 1.5 (5.5) meV without (with) the spin detection mode, compatible with a spatial resolution better than 10 textmum. This enables us to probe both spatially-resolved electronic structures and vector information of spin polarization in three dimensions. The performance of textmu-SARPES apparatus is demonstrated by presenting ARPES and SARPES results from topological insulators and Au photolithography patterns on a Si (001) substrate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{D3NR03830K,

title = {Emergence of quasi-1D spin-polarized states in ultrathin Bi films on InAs(111)A for spintronics applications},

author = {Alexey N. Mihalyuk and Leonid V. Bondarenko and Alexandra Y. Tupchaya and Dimitry V. Gruznev and Nadezhda Yu. Solovova and Vladimir A. Golyashov and Oleg E. Tereshchenko and Taichi Okuda and Akio Kimura and Sergey V. Eremeev and Andrey V. Zotov and Alexander A. Saranin},

url = {http://dx.doi.org/10.1039/D3NR03830K},

doi = {10.1039/D3NR03830K},

year  = {2024},

date = {2024-01-01},

journal = {Nanoscale},

volume = {16},

pages = {1272-1281},

publisher = {The Royal Society of Chemistry},

abstract = {The discovery, characterization, and control of heavy-fermion low-dimensional materials are central to nanoscience since quantum phenomena acquire an exotic and highly tunable character. In this work, through a variety of comprehensive experimental and theoretical techniques, it was observed and predicted that the synthesis of ultrathin Bi films on the InAs(111)A surface produces quasi-one-dimensional spin-polarized states, providing a platform for the realization of a unique spin-transport regime in the system. Scanning tunneling microscopy and low-energy electron diffraction measurements revealed that the InAs(111)A substrate facilitates the formation of the Bi-dimer phase of 2√3 × 3 periodicity with an admixture of the Bi-bilayer phase under submonolayer Bi deposition. X-ray photoelectron spectroscopy (XPS) measurements have shown the chemical stability of the Bi-induced phases, while spin and angle resolved photoemission spectroscopy (SARPES) observations combined with state-of-the-art DFT calculations have revealed that the electronic spectrum of the Bi-dimer phase holds a quasi-1D hole-like spin-split state at the Fermi level with advanced spin texture, whereas the Bi-bilayer phase demonstrates metallic states with large Rashba spin-splitting. The band structure of the Bi/InAs(111)A interface is discovered to hold great potential as a high-performance spintronics material fabricated in the ultimate two-dimensional limit.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{10.1093/jmicro/dfae021,

title = {Spin polarization of photoelectrons emitted from spin-orbit coupled surface states of Pb/Ge(111)},

author = {Koichiro Yaji and Kenta Kuroda and Shunsuke Tsuda and Fumio Komori},

url = {https://doi.org/10.1093/jmicro/dfae021},

doi = {10.1093/jmicro/dfae021},

year  = {2024},

date = {2024-01-01},

journal = {Microscopy},

pages = {dfae021},

abstract = {We report that the spin vector of photoelectrons emitted from an atomic layer Pb grown on a germanium substrate [Pb/Ge(111)] can be controlled using an electric field of light. The spin polarization of photoelectrons excited by a linearly polarized light is precisely investigated by spin- and angle-resolved photoemission spectroscopy. The spin polarization of the photoelectrons observed in the mirror plane reverses between p- and s-polarized lights. Considering the dipole transition selection rule, the surface state of Pb/Ge(111) is represented by a linear combination of symmetric and asymmetric orbital components coupled with spins in mutually opposite directions. The spin direction of the photoelectrons is different from that of the initial state when the electric field vector of linearly polarized light deviates from p- or s-polarization conditions. The quantum interference in the photoexcitation process can determine the direction of the spin vector of photoelectrons.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.108.L241101,

title = {Role of on-site Coulomb interactions in the half-metallic Weyl ferromagnet candidate thin-film Co2FeSi},

author = {Kazuki Sumida and Yuichi Fujita and Weinan Zhou and Keisuke Masuda and Ikuto Kawasaki and Shin-ichi Fujimori and Akio Kimura and Yuya Sakuraba},

url = {https://link.aps.org/doi/10.1103/PhysRevB.108.L241101},

doi = {10.1103/PhysRevB.108.L241101},

year  = {2023},

date = {2023-12-01},

urldate = {2023-12-01},

journal = {Phys. Rev. B},

volume = {108},

pages = {L241101},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevMaterials.7.114201,

title = {Creation of a $p$-type $mathrmTlBiSe_2$ using photo-induced doping},

author = {Ryota Itaya and Yuichiro Toichi and Ryuya Nakanishi and Narunori Ebara and Yoshitaka Nakata and Kentaro Kasai and Kenta Kuroda and Masashi Arita and Isamu Yamamoto and Keisuke Fukutani and Kazuyuki Sakamoto},

url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.7.114201},

doi = {10.1103/PhysRevMaterials.7.114201},

year  = {2023},

date = {2023-11-01},

urldate = {2023-11-01},

journal = {Phys. Rev. Mater.},

volume = {7},

issue = {11},

pages = {114201},

publisher = {American Physical Society},

abstract = {Owing to the location of the Dirac point, which is around the center of its wide bulk band gap, TlBiSe2 would be one of the most promising topological insulators for spintronics devices material. However, like many other topological insulators, defects, such as vacancy formed during the crystal growth, dope electrons into TlBiSe2 and make its bulk metallic. Here, we show the achievement of bulk insulating both n-type and p-type TlBiSe2 by photo-induced doping, a method carried out by a combination of photo-irradiation and H2O adsorption. We also show that the main trigger of this photo-induced doping is the excitation of the outermost d core level of the chalcogen atoms of the topmost layer as in the case of Bi2X3, where X=Se or Te.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.107.235306,

title = {Boosting the surface conduction in a topological insulator},

author = {M. Taupin and G. Eguchi and M. Luifmmode checkzelse žfinik and A. Steiger-Thirsfeld and Y. Ishida and K. Kuroda and S. Shin and A. Kimura and S. Paschen},

url = {https://link.aps.org/doi/10.1103/PhysRevB.107.235306},

doi = {10.1103/PhysRevB.107.235306},

year  = {2023},

date = {2023-06-01},

journal = {Phys. Rev. B},

volume = {107},

issue = {23},

pages = {235306},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.130.186402,

title = {Semiconducting Electronic Structure of the Ferromagnetic Spinel HgCr2Se4 Revealed by Soft-X-Ray Angle-Resolved Photoemission Spectroscopy},

author = {Hiroaki Tanaka and Andrei V. Telegin and Yurii P. Sukhorukov and Vladimir A. Golyashov and Oleg E. Tereshchenko and Alexander N. Lavrov and Takuya Matsuda and Ryusuke Matsunaga and Ryosuke Akashi and Mikk Lippmaa and Yosuke Arai and Shinichiro Ideta and Kiyohisa Tanaka and Takeshi Kondo and Kenta Kuroda},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.130.186402},

doi = {10.1103/PhysRevLett.130.186402},

year  = {2023},

date = {2023-05-01},

urldate = {2023-05-01},

journal = {Phys. Rev. Lett.},

volume = {130},

issue = {18},

pages = {186402},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TANAKA2023147297,

title = {SPADExp: A photoemission angular distribution simulator directly linked to first-principles calculations},

author = {Hiroaki Tanaka and Kenta Kuroda and Tomohiro Matsushita},

url = {https://www.sciencedirect.com/science/article/pii/S0368204823000142},

doi = {https://doi.org/10.1016/j.elspec.2023.147297},

issn = {0368-2048},

year  = {2023},

date = {2023-01-01},

journal = {Journal of Electron Spectroscopy and Related Phenomena},

volume = {264},

pages = {147297},

abstract = {We develop a software package SPADExp (simulator of photoemission angular distribution for experiments) to calculate the photoemission angular distribution (PAD), which is the momentum dependence of spectrum intensity in angle-resolved photoemission spectroscopy (ARPES). The software can directly load the output of the first-principles software package OpenMX, so users do not need to construct tight-binding models as previous studies did for PAD calculations. As a result, we can calculate the PADs of large systems such as quasicrystals and slab systems. We calculate the PADs of sublattice systems (graphene and graphite) to reproduce characteristic intensity distributions, which ARPES has experimentally observed. After that, we investigate twisted bilayer graphene, a quasicrystal showing 12-fold rotational symmetric spectra in ARPES, and the surface states of the topological insulator Bi2Se3. Our calculations show good agreement with previous ARPES measurements, showing the correctness of our calculation software and further potential to investigate the photoemission spectra of novel quantum materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Reimann2023,

title = {Ultrafast electron dynamics in a topological surface state observed in two-dimensional momentum space},

author = {J. Reimann and K. Sumida and M. Kakoki and K. A. Kokh and O. E. Tereshchenko and A. Kimura and J. Güdde and U. Höfer},

url = {https://doi.org/10.1038/s41598-023-32811-1},

doi = {10.1038/s41598-023-32811-1},

year  = {2023},

date = {2023-01-01},

journal = {Scientific Reports},

volume = {13},

pages = {5796},

abstract = {We study ultrafast population dynamics in the topological surface state of Sb$$_2$$Te$$_3$$in two-dimensional momentum space with time- and angle-resolved two-photon photoemission spectroscopy. Linearly polarized mid-infrared pump pulses are used to permit a direct optical excitation across the Dirac point. We show that this resonant excitation is strongly enhanced within the Dirac cone along three of the six $$backslashbarbackslashGamma $$--$$backslashbarM$$directions and results in a macroscopic photocurrent when the plane of incidence is aligned along a $$backslashbarbackslashGamma $$--$$backslashbarK$$direction. Our experimental approach makes it possible to disentangle the decay of transiently excited population and photocurent by elastic and inelastic electron scattering within the full Dirac cone in unprecedented detail. This is utilized to show that doping of Sb$$_2$$Te$$_3$$by vanadium atoms strongly enhances inelastic electron scattering to lower energies, but only scarcely affects elastic scattering around the Dirac cone.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{fukushima2023spin,

title = {Spin-polarized saddle points in the topological surface states of the elemental Bismuth revealed by a pump-probe spin-resolved ARPES},

author = {Yuto Fukushima and Kaishu Kawaguchi and Kenta Kuroda and Masayuki Ochi and Hiroaki Tanaka and Ayumi Harasawa and Takushi Iimori and Zhigang Zhao and Shuntaro Tani and Koichiro Yaji and others},

url = {https://arxiv.org/abs/2303.17816},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {arXiv preprint arXiv:2303.17816},

abstract = {We use a pump-probe, spin-, and angle-resolved photoemission spectroscopy (ARPES) with a 10.7 eV laser accessible up to the Brillouin zone edge, and reveal for the first time the entire band structure, including the unoccupied side, for the elemental bismuth (Bi) with the spin-polarized surface states. Our data identify Bi as in a strong topological insulator phase (Z2=1) against the prediction of most band calculations. We unveil that the unoccupied topological surface states possess spin-polarized saddle points yielding the van Hove singularity, providing an excellent platform for the future development of opto-spintronics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.107.L241101,

title = {Evidence for three-dimensional Dirac conical bands in TlBiSSe by optical and magneto-optical spectroscopy},

author = {F. Le Mardelé and J. Wyzula and I. Mohelsky and S. Nasrallah and M. Loh and S. Ben David and O. Toledano and D. Tolj and M. Novak and G. Eguchi and S. Paschen and N. Bariifmmode checkselse šfiiifmmode acutecelse ćfi and J. Chen and A. Kimura and M. Orlita and Z. Rukelj and Ana Akrap and D. Santos-Cottin},

url = {https://link.aps.org/doi/10.1103/PhysRevB.107.L241101},

doi = {10.1103/PhysRevB.107.L241101},

year  = {2023},

date = {2023-01-01},

journal = {Phys. Rev. B},

volume = {107},

issue = {24},

pages = {L241101},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{10.1063/5.0151859,

title = {Time-, spin-, and angle-resolved photoemission spectroscopy with a 1-MHz 10.7-eV pulse laser},

author = {Kaishu Kawaguchi and Kenta Kuroda and Z. Zhao and S. Tani and A. Harasawa and Y. Fukushima and H. Tanaka and R. Noguchi and T. Iimori and K. Yaji and M. Fujisawa and S. Shin and F. Komori and Y. Kobayashi and Takeshi Kondo},

url = {https://doi.org/10.1063/5.0151859},

doi = {10.1063/5.0151859},

year  = {2023},

date = {2023-01-01},

journal = {Review of Scientific Instruments},

volume = {94},

number = {8},

pages = {083902},

abstract = {We describe a setup of time-, spin-, and angle-resolved photoemission spectroscopy (tr-SARPES) employing a 10.7 eV (λ = 115.6 nm) pulse laser at a 1 MHz repetition rate as a probe photon source. This equipment effectively combines the technologies of a high-power Yb:fiber laser, ultraviolet-driven harmonic generation in Xe gas, and a SARPES apparatus equipped with very-low-energy-electron-diffraction spin detectors. A high repetition rate (1 MHz) of the probe laser allows experiments with the photoemission space-charge effects significantly reduced, despite a high flux of 1013 photons/s on the sample. The relatively high photon energy (10.7 eV) also brings the capability of observing a wide momentum range that covers the entire Brillouin zone of many materials while ensuring high momentum resolution. The experimental setup overcomes the low efficiency of spin-resolved measurements, which gets even more severe for the pump-probed unoccupied states, and affords the opportunity to investigate ultrafast electron and spin dynamics of modern quantum materials with energy and time resolutions of 25 meV and 360 fs, respectively.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{tanaka2023broken,

title = {Broken Screw Rotational Symmetry in the Near-Surface Electronic Structure of $AB$-Stacked Crystals},

author = {Hiroaki Tanaka and Shota Okazaki and Masaru Kobayashi and Yuto Fukushima and Yosuke Arai and Takushi Iimori and Mikk Lippmaa and Kohei Yamagami and Yoshinori Kotani and Fumio Komori and Kenta Kuroda and Takao Sasagawa and Takeshi Kondo},

url = {https://arxiv.org/abs/2308.00999},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

journal = {arXiv preprint arXiv:2308.00999},

abstract = {We investigate the electronic structure of 2H-NbS2 and hBN by angle-resolved photoemission spectroscopy (ARPES) and photoemission intensity calculations. Although in bulk form, these materials are expected to exhibit band degeneracy in the kz=π/c plane due to screw rotation and time-reversal symmetries, we observe gapped band dispersion near the surface. We extract from first-principles calculations the near-surface electronic structure probed by ARPES and find that the calculated photoemission spectra from the near-surface region reproduce the gapped ARPES spectra. Our results show that the near-surface electronic structure can be qualitatively different from the bulk one due to partially broken nonsymmorphic symmetries.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.7566/JPSJ.92.084706,

title = {One-Dimensional Band Structure in Quasi-Two-Dimensional η-Mo4O11 Revealed by Angle-Resolved Photoelectron Spectroscopy and First-Principles Calculation},

author = {Kazuki Sumida and Sota Higaki and Hitoshi Sato and Daichi Tsuru and Koji Miyamoto and Taichi Okuda and Yoshihiro Kuroiwa and Chikako Moriyoshi and Kouichi Takase and Tamio Oguchi and Akio Kimura},

url = {https://doi.org/10.7566/JPSJ.92.084706},

doi = {10.7566/JPSJ.92.084706},

year  = {2023},

date = {2023-01-01},

journal = {Journal of the Physical Society of Japan},

volume = {92},

number = {8},

pages = {084706},

abstract = {We investigated the electronic structure of η-Mo4O11 bulk crystal in the whole Brillouin zone in its normal metallic phase by utilizing resonant and angle-resolved photoelectron spectroscopies and first-principles calculations. Mo 4p-4d resonant photoelectron experiment revealed that the Mo 4d electrons of MoO6 octahedra mainly contributed to the electrical conductivity. We also demonstrated that the free electron-like band dispersions along kb axis, consisting of Mo 4dxy electrons, do not show clear ka and kc dependences and formed a one-dimensional Fermi surface even in the normal phase. The observed low-dimensional and anisotropic band structures are expected to give rise to exotic physical properties such as quantized bulk Hall effect, charge density wave transitions, and Luttinger liquid behavior.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.129.146401,

title = {Coexistence of Strong and Weak Topological Orders in a Quasi-One-Dimensional Material},

author = {De-Yang Wang and Qi Jiang and Kenta Kuroda and Kaishu Kawaguchi and Ayumi Harasawa and Koichiro Yaji and Arthur Ernst and Hao-Ji Qian and Wen-Jing Liu and He-Ming Zha and Zhi-Cheng Jiang and Ni Ma and Hong-Ping Mei and Ang Li and Takeshi Kondo and Shan Qiao and Mao Ye},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.129.146401},

doi = {10.1103/PhysRevLett.129.146401},

year  = {2022},

date = {2022-09-01},

journal = {Phys. Rev. Lett.},

volume = {129},

pages = {146401},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.106.085114,

title = {Anomalously large spin-dependent electron correlation in the nearly half-metallic ferromagnet CoS2},

author = {Hirokazu Fujiwara and Kensei Terashima and Junya Otsuki and Nayuta Takemori and Harald O. Jeschke and Takanori Wakita and Yuko Yano and Wataru Hosoda and Noriyuki Kataoka and Atsushi Teruya and Masashi Kakihana and Masato Hedo and Takao Nakama and Yoshichika Ōfinuki and Koichiro Yaji and Ayumi Harasawa and Kenta Kuroda and Shik Shin and Koji Horiba and Hiroshi Kumigashira and Yuji Muraoka and Takayoshi Yokoya},

url = {https://link.aps.org/doi/10.1103/PhysRevB.106.085114},

doi = {10.1103/PhysRevB.106.085114},

year  = {2022},

date = {2022-08-01},

urldate = {2022-08-01},

journal = {Phys. Rev. B},

volume = {106},

pages = {085114},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevMaterials.6.074403,

title = {Rhombic Fermi surfaces in a ferromagnetic MnGa thin film with perpendicular magnetic anisotropy},

author = {M. Kobayashi and N. H. D. Khang and T. Takeda and K. Araki and R. Okano and M. Suzuki and K. Kuroda and K. Yaji and K. Sugawara and S. Souma and K. Nakayama and K. Yamauchi and M. Kitamura and K. Horiba and A. Fujimori and T. Sato and S. Shin and M. Tanaka and P. N. Hai},

url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.6.074403},

doi = {10.1103/PhysRevMaterials.6.074403},

year  = {2022},

date = {2022-07-01},

journal = {Phys. Rev. Materials},

volume = {6},

pages = {074403},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.L241115,

title = {Nodal-line driven anomalous susceptibility in ZrSiS},

author = {Bruno Gudac and Markus Kriener and Yuriy V. Sharlai and Mihovil Bosnar and Filip Orbaniıfmmode acutecelse ćfi and Grigorii P. Mikitik and Akio Kimura and Ivan Kokanoviıfmmode acutecelse ćfi and Mario Novak},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.L241115},

doi = {10.1103/PhysRevB.105.L241115},

year  = {2022},

date = {2022-06-01},

journal = {Phys. Rev. B},

volume = {105},

pages = {L241115},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevMaterials.6.044405,

title = {Magnetoelastic anisotropy in Heusler-type $mathrmMn(2-d)CoGa(1+d) films},

author = {Takahide Kubota and Daichi Takano and Yohei Kota and Shaktiranjan Mohanty and Keita Ito and Mitsuhiro Matsuki and Masahiro Hayashida and Mingling Sun and Yukiharu Takeda and Yuji Saitoh and Subhankar Bedanta and Akio Kimura and Koki Takanashi},

url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.6.044405},

doi = {10.1103/PhysRevMaterials.6.044405},

year  = {2022},

date = {2022-04-01},

urldate = {2022-04-01},

journal = {Phys. Rev. Mater.},

volume = {6},

pages = {044405},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.L121103,

title = {Evidence for Dirac nodal-line fermions in a phosphorous square-net superconductor},

author = {S. Ishizaka and A. Ino and T. Kono and Y. Miyai and S. Kumar and K. Shimada and H. Kit^o and I. Hase and S. Ishida and K. Oka and H. Fujihisa and Y. Gotoh and Y. Yoshida and A. Iyo and H. Ogino and H. Eisaki and K. Kawashima and Y. Yanagi and A. Kimura},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.L121103},

doi = {10.1103/PhysRevB.105.L121103},

year  = {2022},

date = {2022-03-01},

journal = {Phys. Rev. B},

volume = {105},

pages = {L121103},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.L121102,

title = {Large anomalous Hall effect induced by weak ferromagnetism in the noncentrosymmetric antiferromagnet CoNb3S6},

author = {Hiroaki Tanaka and Shota Okazaki and Kenta Kuroda and Ryo Noguchi and Yosuke Arai and Susumu Minami and Shinichiro Ideta and Kiyohisa Tanaka and Donghui Lu and Makoto Hashimoto and Viktor Kandyba and Mattia Cattelan and Alexei Barinov and Takayuki Muro and Takao Sasagawa and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.L121102},

doi = {10.1103/PhysRevB.105.L121102},

year  = {2022},

date = {2022-03-01},

urldate = {2022-03-01},

journal = {Phys. Rev. B},

volume = {105},

pages = {L121102},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.L121106,

title = {Visualization of optical polarization transfer to photoelectron spin vector emitted from a spin-orbit coupled surface state},

author = {Kenta Kuroda and Koichiro Yaji and Ryo Noguchi and Ayumi Harasawa and Shik Shin and Takeshi Kondo and Fumio Komori},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.L121106},

doi = {10.1103/PhysRevB.105.L121106},

year  = {2022},

date = {2022-03-01},

journal = {Phys. Rev. B},

volume = {105},

pages = {L121106},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Arai2022,

title = {Multipole polaron in the devil's staircase of CeSb},

author = {Y. Arai and Kenta Kuroda and T. Nomoto and Z. H. Tin and S. Sakuragi and C. Bareille and S. Akebi and K. Kurokawa and Y. Kinoshita and W. -L. Zhang and S. Shin and M. Tokunaga and H. Kitazawa and Y. Haga and H. S. Suzuki and S. Miyasaka and S. Tajima and K. Iwasa and R. Arita and Takeshi Kondo},

url = {https://doi.org/10.1038/s41563-021-01188-9},

doi = {10.1038/s41563-021-01188-9},

year  = {2022},

date = {2022-02-10},

urldate = {2022-02-10},

journal = {Nature Materials},

volume = {21},

pages = {410–415},

abstract = {Rare-earth intermetallic compounds exhibit rich phenomena induced by the interplay between localized f orbitals and conduction electrons. However, since the energy scale of the crystal-electric-field splitting is only a few millielectronvolts, the nature of the mobile electrons accompanied by collective crystal-electric-field excitations has not been unveiled. Here, we examine the low-energy electronic structures of CeSb through the anomalous magnetostructural transitions below the Néel temperature, textasciitilde17thinspaceK, termed the `devil's staircase', using laser angle-resolved photoemission, Raman and neutron scattering spectroscopies. We report another type of electron--boson coupling between mobile electrons and quadrupole crystal-electric-field excitations of the 4f orbitals, which renormalizes the Sb 5p band prominently, yielding a kink at a very low energy (textasciitilde7thinspacemeV). This coupling strength is strong and exhibits anomalous step-like enhancement during the devil's staircase transition, unveiling a new type of quasiparticle, named the `multipole polaron', comprising a mobile electron dressed with a cloud of the quadrupole crystal-electric-field polarization.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.085421,

title = {Selective observation of surface and bulk bands in polar WTe2 by laser-based spin- and angle-resolved photoemission spectroscopy},

author = {Yuxuan Wan and Lihai Wang and Kenta Kuroda and Peng Zhang and Keisuke Koshiishi and Masahiro Suzuki and Jaewook Kim and Ryo Noguchi and Cédric Bareille and Koichiro Yaji and Ayumi Harasawa and Shik Shin and Sang-Wook Cheong and Atsushi Fujimori and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.085421},

doi = {10.1103/PhysRevB.105.085421},

year  = {2022},

date = {2022-02-01},

urldate = {2022-02-01},

journal = {Phys. Rev. B},

volume = {105},

pages = {085421},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shikin2021,

title = {Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI},

author = {A. M. Shikin and A. A. Rybkina and D. A. Estyunin and I. I. Klimovskikh and A. G. Rybkin and S. O. Filnov and A. V. Koroleva and E. V. Shevchenko and M. V. Likholetova and V. Yu. Voroshnin and A. E. Petukhov and K. A. Kokh and O. E. Tereshchenko and L. Petaccia and G. Di Santo and S. Kumar and A. Kimura and P. N. Skirdkov and K. A. Zvezdin and A. K. Zvezdin},

url = {https://doi.org/10.1038/s41598-021-02493-8},

doi = {10.1038/s41598-021-02493-8},

year  = {2021},

date = {2021-12-02},

journal = {Scientific Reports},

volume = {11},

pages = {23332},

abstract = {Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.104.L180409,

title = {Scaling law for Rashba-type spin splitting in quantum-well films},

author = {Ryo Noguchi and Kenta Kuroda and Mitsuaki Kawamura and Koichiro Yaji and Ayumi Harasawa and Takushi Iimori and Shik Shin and Fumio Komori and Taisuke Ozaki and Takeshi Kondo},

url = {https://link.aps.org/doi/10.1103/PhysRevB.104.L180409},

doi = {10.1103/PhysRevB.104.L180409},

year  = {2021},

date = {2021-11-01},

urldate = {2021-11-01},

journal = {Phys. Rev. B},

volume = {104},

pages = {L180409},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.104.195112,

title = {Three-dimensional bulk Fermi surfaces and Weyl crossings of $mathrmCo_2mathrmMnGa$ thin films underneath a protection layer},

author = {Takashi Kono and Masaaki Kakoki and Tomoki Yoshikawa and Xiaoxiao Wang and Kazuki Sumida and Takayuki Muro and Kazuki Goto and Yuya Sakuraba and Rie Y. Umetsu and Akio Kimura},

url = {https://link.aps.org/doi/10.1103/PhysRevB.104.195112},

doi = {10.1103/PhysRevB.104.195112},

year  = {2021},

date = {2021-11-01},

journal = {Phys. Rev. B},

volume = {104},

pages = {195112},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.104.115168,

title = {Sample-dependent Dirac-point gap in $mathrmMnBi_2mathrmTe_4$ and its response to applied surface charge: A combined photoemission and ab initio study},

author = {A. M. Shikin and D. A. Estyunin and N. L. Zaitsev and D. Glazkova and I. I. Klimovskikh and S. O. Filnov and A. G. Rybkin and E. F. Schwier and S. Kumar and A. Kimura and N. Mamedov and Z. Aliev and M. B. Babanly and K. Kokh and O. E. Tereshchenko and M. M. Otrokov and E. V. Chulkov and K. A. Zvezdin and A. K. Zvezdin},

url = {https://link.aps.org/doi/10.1103/PhysRevB.104.115168},

doi = {10.1103/PhysRevB.104.115168},

year  = {2021},

date = {2021-09-01},

journal = {Phys. Rev. B},

volume = {104},

pages = {115168},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lin2021,

title = {Visualization of the strain-induced topological phase transition in a quasi-one-dimensional superconductor TaSe3},

author = {Chun Lin and Masayuki Ochi and Ryo Noguchi and Kenta Kuroda and Masahito Sakoda and Atsushi Nomura and Masakatsu Tsubota and Peng Zhang and Cedric Bareille and Kifu Kurokawa and Yosuke Arai and Kaishu Kawaguchi and Hiroaki Tanaka and Koichiro Yaji and Ayumi Harasawa and Makoto Hashimoto and Donghui Lu and Shik Shin and Ryotaro Arita and Satoshi Tanda and Takeshi Kondo},

url = {https://doi.org/10.1038/s41563-021-01004-4},

doi = {10.1038/s41563-021-01004-4},

year  = {2021},

date = {2021-08-01},

urldate = {2021-08-01},

journal = {Nature Materials},

volume = {20},

number = {8},

pages = {1093-1099},

abstract = {Control of the phase transition from topological to normal insulators can allow for an on/off switching of spin current. While topological phase transitions have been realized by elemental substitution in semiconducting alloys, such an approach requires preparation of materials with various compositions. Thus it is quite far from a feasible device application, which demands a reversible operation. Here we use angle-resolved photoemission spectroscopy and spin- and angle-resolved photoemission spectroscopy to visualize the strain-driven band-structure evolution of the quasi-one-dimensional superconductor TaSe3. We demonstrate that it undergoes reversible strain-induced topological phase transitions from a strong topological insulator phase with spin-polarized, quasi-one-dimensional topological surface states, to topologically trivial semimetal and band insulating phases. The quasi-one-dimensional superconductor TaSe3 provides a suitable platform for engineering the topological spintronics, for example as an on/off switch for a spin current that is robust against impurity scattering.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sakamoto2021,

title = {Spatial Control of Charge Doping in n-Type Topological Insulators},

author = {Kazuyuki Sakamoto and Hirotaka Ishikawa and Takashi Wake and Chie Ishimoto and Jun Fujii and Hendrik Bentmann and Minoru Ohtaka and Kenta Kuroda and Natsu Inoue and Takuma Hattori and Toshio Miyamachi and Fumio Komori and Isamu Yamamoto and Cheng Fan and Peter Krüger and Hiroshi Ota and Fumihiko Matsui and Friedrich Reinert and José Avila and Maria C. Asensio},

url = {https://doi.org/10.1021/acs.nanolett.1c01100},

doi = {10.1021/acs.nanolett.1c01100},

year  = {2021},

date = {2021-05-26},

journal = {Nano Letters},

volume = {21},

pages = {4415-4422},

publisher = {American Chemical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Noguchi2021,

title = {Evidence for a higher-order topological insulator in a three-dimensional material built from van der Waals stacking of bismuth-halide chains},

author = {Ryo Noguchi and Masaru Kobayashi and Zhanzhi Jiang and Kenta Kuroda and Takanari Takahashi and Zifan Xu and Daehun Lee and Motoaki Hirayama and Masayuki Ochi and Tetsuroh Shirasawa and Peng Zhang and Chun Lin and Cédric Bareille and Shunsuke Sakuragi and Hiroaki Tanaka and So Kunisada and Kifu Kurokawa and Koichiro Yaji and Ayumi Harasawa and Viktor Kandyba and Alessio Giampietri and Alexei Barinov and Timur K. Kim and Cephise Cacho and Makoto Hashimoto and Donghui Lu and Shik Shin and Ryotaro Arita and Keji Lai and Takao Sasagawa and Takeshi Kondo},

url = {https://doi.org/10.1038/s41563-020-00871-7},

doi = {10.1038/s41563-020-00871-7},

year  = {2021},

date = {2021-04-01},

journal = {Nature Materials},

volume = {20},

pages = {473-479},

abstract = {Low-dimensional van der Waals materials have been extensively studied as a platform with which to generate quantum effects. Advancing this research, topological quantum materials with van der Waals structures are currently receiving a great deal of attention. Here, we use the concept of designing topological materials by the van der Waals stacking of quantum spin Hall insulators. Most interestingly, we find that a slight shift of inversion centre in the unit cell caused by a modification of stacking induces a transition from a trivial insulator to a higher-order topological insulator. Based on this, we present angle-resolved photoemission spectroscopy results showing that the real three-dimensional material Bi4Br4 is a higher-order topological insulator. Our demonstration that various topological states can be selected by stacking chains differently, combined with the advantages of van der Waals materials, offers a playground for engineering topologically non-trivial edge states towards future spintronics applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.103.L060403,

title = {Itinerant ferromagnetism mediated by giant spin polarization of the metallic ligand band in the van der Waals magnet Fe5GeTe2},

author = {K. Yamagami and Y. Fujisawa and B. Driesen and C. H. Hsu and K. Kawaguchi and H. Tanaka and T. Kondo and Y. Zhang and H. Wadati and K. Araki and T. Takeda and Y. Takeda and T. Muro and F. C. Chuang and Y. Niimi and K. Kuroda and M. Kobayashi and Y. Okada},

url = {https://link.aps.org/doi/10.1103/PhysRevB.103.L060403},

doi = {10.1103/PhysRevB.103.L060403},

year  = {2021},

date = {2021-02-01},

urldate = {2021-02-01},

journal = {Phys. Rev. B},

volume = {103},

issue = {6},

pages = {L060403},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ye2021,

title = {Persistence of the Topological Surface States in Bi2Se3 against Ag Intercalation at Room Temperature},

author = {Mao Ye and Kenta Kuroda and Mikhail M. Otrokov and Anastasia G. Ryabishchenkova and Qi Jiang and Arthur Ernst and Evgueni V. Chulkov and Masashi Nakatake and Masashi Arita and Taichi Okuda and Tomohiro Matsushita and László Tóth and Hiroshi Daimon and Kenya Shimada and Yoshifumi Ueda and Akio Kimura},

url = {https://doi.org/10.1021/acs.jpcc.0c07462},

doi = {10.1021/acs.jpcc.0c07462},

year  = {2021},

date = {2021-01-28},

journal = {The Journal of Physical Chemistry C},

volume = {125},

pages = {1784-1792},

publisher = {American Chemical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Zhang2021,

title = {Observation and control of the weak topological insulator state in ZrTe5},

author = {Peng Zhang and Ryo Noguchi and Kenta Kuroda and Chun Lin and Kaishu Kawaguchi and Koichiro Yaji and Ayumi Harasawa and Mikk Lippmaa and Simin Nie and Hongming Weng and V. Kandyba and A. Giampietri and A. Barinov and Qiang Li and G. D. Gu and Shik Shin and Takeshi Kondo},

url = {https://doi.org/10.1038/s41467-020-20564-8},

doi = {10.1038/s41467-020-20564-8},

year  = {2021},

date = {2021-01-18},

urldate = {2021-01-18},

journal = {Nature Communications},

volume = {12},

pages = {406},

abstract = {A quantum spin Hall (QSH) insulator hosts topological states at the one-dimensional (1D) edge, along which backscattering by nonmagnetic impurities is strictly prohibited. Its 3D analogue, a weak topological insulator (WTI), possesses similar quasi-1D topological states confined at side surfaces. The enhanced confinement could provide a route for dissipationless current and better advantages for applications relative to strong topological insulators (STIs). However, the topological side surface is usually not cleavable and is thus hard to observe. Here, we visualize the topological states of the WTI candidate ZrTe5 by spin and angle-resolved photoemission spectroscopy (ARPES): a quasi-1D band with spin-momentum locking was revealed on the side surface. We further demonstrate that the bulk band gap is controlled by external strain, realizing a more stable WTI state or an ideal Dirac semimetal (DS) state. The highly directional spin-current and the tunable band gap in ZrTe5 will provide an excellent platform for applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{SUMIDA2021100628b,

title = {Ultrafast surface Dirac fermion dynamics of Sb2Te3-based topological insulators},

author = {Kazuki Sumida and Yukiaki Ishida and Jens Güdde and Ulrich Höfer and Shik Shin and Akio Kimura},

url = {https://www.sciencedirect.com/science/article/pii/S0079681621000162},

doi = {https://doi.org/10.1016/j.progsurf.2021.100628},

year  = {2021},

date = {2021-01-01},

journal = {Progress in Surface Science},

volume = {96},

pages = {100628},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MIYASHITA2021114180,

title = {Emergence of low-energy electronic states in oxygen-controlled Mott insulator Ca2RuO4+δ},

author = {Takeo Miyashita and Hideaki Iwasawa and Tomoki Yoshikawa and Shusuke Ozawa and Hironoshin Oda and Takayuki Muro and Hiroki Ogura and Tatsuhiro Sakami and Fumihiko Nakamura and Akihiro Ino},

url = {https://www.sciencedirect.com/science/article/pii/S0038109820306724},

doi = {https://doi.org/10.1016/j.ssc.2020.114180},

issn = {0038-1098},

year  = {2021},

date = {2021-01-01},

journal = {Solid State Communications},

volume = {326},

pages = {114180},

abstract = {Insulator-to-metal transition in Ca2RuO4 has drawn keen attention because of its sensitivity to various stimulation and its potential controllability. Here, we report a direct observation of Fermi surface, which emerges upon introducing excess oxygen into an insulating Ca2RuO4, by using angle-resolved photoemission spectroscopy. Comparison between energy distribution curves shows that the Mott insulating gap is closed by eV-scale spectral-weight transfer with excess oxygen. Momentum-space mapping exhibits two square-shaped sheets of the Fermi surface. One is a hole-like α sheet around the corner of a tetragonal Brillouin zone, and the other is an electron-like β sheet around the Γ point. The electron occupancies of the α and β bands are determined to be nα=1.6 and nβ=0.6, respectively. Our result indicates that the insulator-to-metal transition occurs selectively in dxz and dyz bands and not yet in dxy band. This orbital selectivity is most likely explained in terms of the energy level of dxy, which is deeper for Ca2RuO4+δ than for Ca1.8Sr0.2RuO4. Consequently, we found substantial differences from the Fermi surface of other ruthenates, shedding light on a unique role of excess oxygen among the metallization methods of Ca2RuO4.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{SUMIDA2021100628,

title = {Ultrafast surface Dirac fermion dynamics of Sb2Te3-based topological insulators},

author = {Kazuki Sumida and Yukiaki Ishida and Jens Güdde and Ulrich Höfer and Shik Shin and Akio Kimura},

url = {https://www.sciencedirect.com/science/article/pii/S0079681621000162},

doi = {https://doi.org/10.1016/j.progsurf.2021.100628},

issn = {0079-6816},

year  = {2021},

date = {2021-01-01},

journal = {Progress in Surface Science},

volume = {96},

number = {2},

pages = {100628},

abstract = {Topological insulators (TIs) characterized by gapless and spin-polarized conical band dispersion on their surfaces have been extensively studied over the last decade. This article reviews our recent works on ultrafast carrier dynamics of Sb2Te3-based nonmagnetic and magnetic TIs by utilizing state-of-the-art femtosecond time- and angle-resolved photoelectron spectroscopy. We have demonstrated that the electronic recovery time elongated from a few ps to >400 ps in case that the Dirac point was close to the Fermi energy in the series of (Sb1-xBix)2Te3. We also investigated how the magnetic-impurity affects the carrier dynamics in ferromagnetic Sb2-yVyTe3. It was found that the electronic recovery time drastically shortened from a few ps to <500 fs with increasing vanadium concentration. Since the lifetime of the nonequilibrated surface Dirac fermions can range from femto- to nano-second, Sb2Te3-based TIs would be promising for ultrafast spin switching and spin-polarized current generation device applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sumida2020,

title = {Spin-polarized Weyl cones and giant anomalous Nernst effect in ferromagnetic Heusler films},

author = {Kazuki Sumida and Yuya Sakuraba and Keisuke Masuda and Takashi Kono and Masaaki Kakoki and Kazuki Goto and Weinan Zhou and Koji Miyamoto and Yoshio Miura and Taichi Okuda and Akio Kimura},

url = {https://doi.org/10.1038/s43246-020-00088-w},

doi = {10.1038/s43246-020-00088-w},

year  = {2020},

date = {2020-11-24},

journal = {Communications Materials},

volume = {1},

pages = {89},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.125.216403,

title = {Visualizing Half-Metallic Bulk Band Structure with Multiple Weyl Cones of the Heusler Ferromagnet},

author = {Takashi Kono and Masaaki Kakoki and Tomoki Yoshikawa and Xiaoxiao Wang and Kazuki Goto and Takayuki Muro and Rie Y. Umetsu and Akio Kimura},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.125.216403},

doi = {10.1103/PhysRevLett.125.216403},

year  = {2020},

date = {2020-11-01},

journal = {Phys. Rev. Lett.},

volume = {125},

pages = {216403},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevResearch.2.043120,

title = {Observation of unoccupied states of SnTe(111) using pump-probe ARPES measurement},

author = {Hiroshi Ito and Yusuke Otaki and Yuta Tomohiro and Yukiaki Ishida and Ryota Akiyama and Akio Kimura and Shik Shin and Shinji Kuroda},

url = {https://link.aps.org/doi/10.1103/PhysRevResearch.2.043120},

doi = {10.1103/PhysRevResearch.2.043120},

year  = {2020},

date = {2020-10-01},

journal = {Phys. Rev. Research},

volume = {2},

pages = {043120},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.102.125151,

title = {Experimental verification of a temperature-induced topological phase transition in $mathrmTlBiS_2$ and $mathrmTlmathrmBimathrmSe_2$},

author = {Takehito Imai and Jiahua Chen and Kazuki Kato and Kenta Kuroda and Teruo Matsuda and Akio Kimura and Koji Miyamoto and Sergey V. Eremeev and Taichi Okuda},

url = {https://link.aps.org/doi/10.1103/PhysRevB.102.125151},

doi = {10.1103/PhysRevB.102.125151},

year  = {2020},

date = {2020-09-01},

journal = {Phys. Rev. B},

volume = {102},

pages = {125151},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shikin2020,

title = {Nature of the Dirac gap modulation and surface magnetic interaction in axion antiferromagnetic topological insulator $$backslashhbox MnBi_2 backslashhbox Te_4$$},

author = {A. M. Shikin and D. A. Estyunin and I. I. Klimovskikh and S. O. Filnov and E. F. Schwier and S. Kumar and K. Miyamoto and T. Okuda and A. Kimura and K. Kuroda and K. Yaji and S. Shin and Y. Takeda and Y. Saitoh and Z. S. Aliev and N. T. Mamedov and I. R. Amiraslanov and M. B. Babanly and M. M. Otrokov and S. V. Eremeev and E. V. Chulkov},

url = {https://doi.org/10.1038/s41598-020-70089-9},

doi = {10.1038/s41598-020-70089-9},

year  = {2020},

date = {2020-08-06},

journal = {Scientific Reports},

volume = {10},

pages = {13226},

keywords = {},

pubstate = {published},

tppubtype = {article}

}