Mizokawa group

Department of Applied Physics

School of Advanced Science and Engineering

Waseda University

 

Members:

P           Takashi Mizokawa       mizokawa at waseda.jp

L           Mario Okawa

M2        Yu Takahashi

M2        Genki Hayashi

M2        Takashi Miyoshino

M2        Keisuke Morita

M1        Keita Saito

M1        Shinnosuke Takaya

M1        Masaki Hattori

M1        Ryo Nakamura

B4         Rinka Iguchi

B4         Atsuhiro Nonaka

B4         Kakeru Hiroki

B4         Hiroki Honda

B4         Ryota Muneda

B4         Yotaro Yamamoto

 

Address: 55N-309A, Nishiwaseda campus, Waseda University

         3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan

 

Selected papers:

Direct observation of multiple conduction-band minima in high-performance thermoelectric SnSe,

Mario Okawa, Yuka Akabane, Mizuki Maeda, Gangjian Tan, Li-Dong Zhao, Mercouri G. Kanatzidis, Takeshi Suzuki, Mari Watanabe, Jiadi Xu, Qianhui Ren, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Shik Shin, Kozo Okazaki, Naurang L. Saini, Takashi Mizokawa, Scripta Materialia 223, 115081 (2023).

 

Ti 3d Electronic States of Hollandite-type BaxTi8O16+ Studied by Cluster-Model and Band-Structure Calculations,

Takashi Miyoshino, Ryo Nakamura, Naurang L. Saini, and Takashi Mizokawa, J. Phys. Soc. Jpn. 91, 124710 (2022).

 

Fermi Surface Geometry of Heavily Hole Doped CaKFe4As4 Revealed by Angle-Resolved Photoemission Spectroscopy,

Souma Hikami, Shigeyuki Ishida, Akira Iyo, Hiroshi Eisaki, Masashi Arita, Shiv Kumar, Eike F. Schwier, Kennya Shimada, Naurang L. Saini, and Takashi Mizokawa, J. Phys. Soc. Jpn. 91, 124704 (2022).

 

Electronic structure reconstruction by trimer formation in CsW2O6 studied by x-ray photoelectron spectroscopy,

R. Nakamura, D. Takegami, A. Melendez-Sans, L. H. Tjeng, M. Okawa, T. Miyoshino, N. L. Saini, M. Kitamura, D. Shiga, H. Kumigashira, M. Yoshimura, K.-D. Tsuei, Y. Okamoto, and T. Mizokawa, Phys. Rev. B 106, 195104 (2022).

 

Orbital dependent band degeneracy and edge states in single layer and AA bilayer honeycomb lattice systems with p orbital degeneracy,

Genki Hayashi1 and Takashi Mizokawa, J. Phys. Commun. 6, 085011 (2022).

 

Domain Dependent Fermi Arcs Observed in a Striped Phase Dichalcogenide,

Takashi Mizokawa, Alexei Barinov, Viktor Kandyba, Alessio Giampietri, Ryoya Matsumoto, Yohei Okamoto, Kou Takubo, Koji Miyamoto, Taichi Okuda, Sunseng Pyon, Hiroyuki Ishii, Kazutaka Kudo, Minoru Nohara, and Naurang L. Saini,

Adv. Quantum Technol. 5, 2200029 (2022).

 

Bulk and surface electronic structure of MnPSe3 revealed by photoemission and x-ray absorption spectroscopy,

Masato Fujii, Tomoyuki Yamaguchi, Takuo Ohkochi, Chandan De, Sang-Wook Cheong, and Takashi Mizokawa,

Phys. Rev. B 106, 035118 (2022).

 

Electronic Structure of Spinel-Type MgTi2O4: Valence Change at Surface and Effect of Fe Substitution for Mg,

Tomoyuki Yamaguchi, Mario Okawa, Hiroki Wadati, Tom Z. Regier, Tom Saitoh, Yasumasa Takagi, Akira Yasui, Masahiko Isobe, Yutaka Ueda, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 91, 074704 (2022).

 

Impact of Co or Cu Substitution for Ni on the Electronic Structure of Ta2NiSe5 Studied by Band Structure Calculations,

Yu Takahashi, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 91, 074714 (2022).

 

Electronic Structure of Ba3Nb5O15 and Ba2SrNb5O15 Studied by Band Calculation and Photoemission Spectroscopy,

Ryo Nakamura, Takashi Miyoshino, Yuhki Kondoh, Tomomasa Kajita, Takuro Katsufuji, Naurang L. Saini, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 91, 064711 (2022).

 

Surface Electronic States and Inclining Surfaces in MoTe2 Probed by Photoemission Spectromicroscopy,

Ryoya Matsumoto, Naurang L. Saini, Alessio Giampietri, Viktor Kandyba, Alexey Barinov, Rajveer Jha, Ryuji Higashinaka, Tatsuma D. Matsuda, Yuji Aoki, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 90, 084704 (2021).

 

Fermi Surface Geometry and Inhomogeneous Electronic States in Pr1.3−xLa0.7CexCuO4 (x = 0.05) with Small Superconducting Volume Fraction,

Yu Matsuzawa, Tomohiro Morita, Masashi Arita, Alessio Giampietri, Viktor Kandyba, Alexey Barinov, Akira Takahashi, Yusuke Nagakubo, Tadashi Adachi, Yoji Koike, Atsushi Fujimori, Naurang L. Saini, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 90, 054704 (2021).

 

Evolution of the Fermi surface in superconductor PrO1-xFxBiS2 (x=0.0, 0.3, and 0.5) revealed by angle-resolved photoemission spectroscopy,

T. Morita, Y. Matsuzawa, S. Kumar, E. F. Schwier, K. Shimada, R. Higashinaka, T. D. Matsuda, Y. Aoki, N. L. Saini, and T. Mizokawa,

Phys. Rev. B 103, 094510 (2021).

 

Interplay between electronic correlation and atomic disorder in a low carrier density 4d transition-metal oxide,

T. Yasuda, Y. Kondo, T. Kajita, K. Murota, D. Ootsuki, Y. Takagi, A. Yasui, N. L. Saini, T. Katsufuji, and T. Mizokawa,

Phys. Rev. B 102, 205133 (2020).

 

Photoinduced Phase Transition from Excitonic Insulator to Semimetal-like State in Ta2Ni1−xCoxSe5 (x = 0.10),

Takumi Mitsuoka, Takeshi Suzuki, Hidenori Takagi, Naoyuki Katayama, Hiroshi Sawa, Minoru Nohara, Mari Watanabe,

Jiadi Xu, Qianhui Ren, Masami Fujisawa, Teruto Kanai, Jiro Itatani, Shik Shin, Kozo Okazaki, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 89, 124703 (2020).

 

Momentum Dependent Band Renormalization and Surface Aging Effect on a Zone Center Electron Pocket

in NaSn2As2 Revealed by Angle-Resolved Photoemission Spectroscopy,

Yuka Akabane, Taiki Shimaiwa, Yosuke Goto, Yoshikazu Mizuguchi, Takayoshi Yokoya, Masashi Arita, Shiv Kumar,

Eike F. Schwier, Kenya Shimada, Naurang L. Saini, and Takashi Mizokawa,

J. Phys. Soc. Jpn. 89, 114707 (2020).

 

Charge correlation in V2OPO4 probed by hard x-ray photoemission spectroscopy,

Kota Murota, Elise Pachoud, J. Paul Attfield, Robert Glaum, Tatsunori Yasuda, Daiki Ootsuki,

Yasumasa Takagi, Akira Yasui, Daniel I. Khomskii, and Takashi Mizokawa,

Phys. Rev. B 101, 235159 (2020).

 

Vanadium 3d charge and orbital states in V2OPO4 probed by x-ray absorption spectroscopy,

Kota Murota, Elise Pachoud, J. Paul Attfield, Robert Glaum, Ronny Sutarto, Kou Takubo, Daniel I. Khomskii, and Takashi Mizokawa,

Phys. Rev. B 101, 245106 (2020).

 

Temperature-dependent evolution of Ti 3d spectral features at surface of BaxTi8O16+,

S. Dash, H. Enomoto, T. Kajita, K. Ono, K. Horiba, M. Kobayashi, H. Kumigashira, V. Kandyba, A. Giampietri,

A. Barinov, F. Stramaglia, N. L. Saini, T. Katsufuji, and T. Mizokawa,

Phys. Rev. B 100, 125153 (2019).

 

Inhomogeneous charge distribution in a self-doped EuFBiS2 superconductor,

T. Sugimoto, E. Paris, K. Terashima, A. Barinov, A. Giampietri, T. Wakita, T. Yokoya, J. Kajitani, R. Higashinaka,

T. D. Matsuda, Y. Aoki, T. Mizokawa, and N. L. Saini,

Phys. Rev. B 100, 064520 (2019).

 

Temperature-dependent valence state within the metallic phase of BaV10O15 probed by hard x-ray photoelectron spectroscopy,

S. Dash, M. Okawa, T. Kajita, T. Yoshino, R. Shimoyama, K. Takahashi, Y. Takahashi, R. Takayanagi, T. Saitoh,

A. Yasui, E. Ikenaga, N. L. Saini, T. Katsufuji, and T. Mizokawa,

Phys. Rev. B 99, 035122 (2019).

 

Orbital-dependent band renormalization in WTe2 revealed by angle-resolved photoemission spectroscopy,

R. Matsumoto, T. Sugimoto, T. Mizokawa, N. L. Saini, M. Arita, R. Jha, R. Higashinaka, T. D. Matsuda, and Y. Aoki,

Phys. Rev. B 98, 205138 (2018).

 

Impact of valence fluctuations on the electronic properties of RO1xFxBiS2,

S. Dash, T. Morita, K. Kurokawa, Y. Matsuzawa, N. L. Saini, N. Yamamoto, Joe Kajitani, R. Higashinaka,

T. D. Matsuda, Y. Aoki, and T. Mizokawa,

Phys. Rev. B 98, 144501 (2018).

 

Anomalous metallic state with strong charge fluctuations in BaxTi8O16+ revealed by hard x-ray photoemission spectroscopy,

S. Dash, T. Kajita, M. Okawa, T. Saitoh, E. Ikenaga, N. L. Saini, T. Katsufuji, and T. Mizokawa,

Phys. Rev. B 97, 165116 (2018).

 

Unusually large chemical potential shift in a degenerate semiconductor: Angle-resolved photoemission study of SnSe and Na-doped SnSe,

M. Maeda, K. Yamamoto, T. Mizokawa, N. L. Saini, M. Arita, H. Namatame, M. Taniguchi, G. Tan, L. D. Zhao, and M. G. Kanatzidis,

Phys. Rev. B 97, 121110(R) (2018).

 

Inhomogeneous electronic states associated with charge-orbital order/disorder in BaV10O15 probed by photoemission spectromicroscopy,

T. Yoshino, K. Wakita, E. Paris, A. Barinov, T. Kajita, T. Katsufuji, V. Kandyba, T. Sugimoto, T. Yokoya, N. L. Saini, and T. Mizokawa,

Phys. Rev. B 96, 115161 (2017).

 

Orbital order and fluctuations in the two-leg ladder materials BaFe2X3 (X=S and Se) and CsFe2Se3 ,

Kou Takubo, Yuichi Yokoyama, Hiroki Wadati, Shun Iwasaki, Takashi Mizokawa, Teak Boyko, Ronny Sutarto, Feizhou He, Kazuki Hashizume, Satoshi Imaizumi, Takuya Aoyama, Yoshinori Imai, and Kenya Ohgushi,

Phys. Rev. B 96, 115157 (2017).

 
Electronic structure and polar catastrophe at the surface of LixCoO2 studied by angle-resolved photoemission spectroscopy,
Y. Okamoto, R. Matsumoto, T. Yagihara, C. Iwai, K. Miyoshi, J. Takeuchi, K. Horiba, M. Kobayashi, K. Ono, H. Kumigashira, N. L. Saini, and T. Mizokawa,

Phys. Rev. B 96, 125147 (2017).

 

previous papers (2004-2014)

 

research projects

 

Photoemission spectroscopy and inverse-photoemission spectroscopy:

Photoelectrons are emitted from solid surfaces on which ultraviolet or x-ray light is shone.

By measuring the energy and momentum of the photoelectrons, we can study occupied states of the solid (photoemission spectroscopy). On the other hand, we can study unoccupied states of the solid by detecting light emitted from surfaces of the solid on which electrons are shone (inverse-photoemission spectroscopy).

We have been developing a high-energy-resolution inverse-photoemission system based on dispersion matching of light and electron. Using the photoemission and inverse-photoemission experiments, we have been studying the electronic structure of bulk and surface of various solids.

 

In particular, we are interested in transition-metal compounds that show rich physical properties such as ferromagnetism, superconductivity, valence transition, and metal-insulator transition. In transition-metal compounds, d-electrons with spin, charge and orbital degrees of freedom are affected by complicated lattice distortions, and show interesting electric and magnetic properties. We have been studying the relationship between the physical properties and electronic structure of transition-metal compounds using experimental methods such as photoemission and inverse-photoemission spectroscopy and theoretical methods such as unrestricted Hartree-Fock calculation.

 

As for new aspects of transition-metal compounds, an interesting question is what kind of new electronic states are realized when d-electrons are confined at solid surface/interface. Another interesting question is how confined d-electrons behave when perturbed by photons. We are trying to answer these questions by studying thin films and nano particles of various transition-metal compounds under laser illumination. Hopefully, the research projects along this line would contribute to development of new optical and energy devices.

 

 

image002

FigureFDispersion matching for inverse-photoemission spectroscopy