RESEARCH

We have performed angle-resolved photoemission spectroscopy (ARPES) of topological insulators by focusing on the control of Dirac-cone surface states and discovery of new topological materials, in collaboration with Segawa and Ando group in ISIR Osaka Univ. In particular, we have succeeded in observing the Dirac cone at the interface, controlling the Dirac-fermion mass, and found novel phenomena called "topological proximity effect" in a hybrid of topological insulator and Rashba metal. Moreover, we have found that SnTe is a new type of topological material called topological crystalline insulator, by observing the double Dirac-cone states protected by the mirror symmetry of crystal.

In this project, we will investigate electronic states of novel topological materials, in particular, Dirac semimetals, Weyl semimetals, and nodal-line semimetals, by utilizing spin-resolved ARPES technique. By also collaborating with groups fabricating high-quality bulk crystals and thin films, we study fine electronic structure in the vicinity of the Fermi level which is closely related to the exotic topological phenomena.

EDUCATION

1997

Bachelor of Science (Physics), Tohoku University

2002

Ph.D. (Science), Tohoku University

PROFESSIONAL EXPERIENCE

2002

JSPS Fellow (PD)

2002

Assistant Professor, Department of Physics, Tohoku University.

2009

Assistant Professor, Center for the Advancement of Higher Education, Tohoku University.

2010

Associate Professor, Department of Physics, Tohoku University.

2017

Professor, Department of Physics, Tohoku University.

HONORS AND AWARDS

2008

Young Scientist Award of the Physical Society of Japan

2009

The Young Scientists' Prize(The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology)

SELECTION OF PUBLICATIONS

"High-temperature superconductivity in potassium-coated multilayer FeSe film"
Y. Miyama, K. Nakayama, K. Sugawara, T. Sato, and T. Takahashi
Nature Materials 14, 775-779 (Jun. 2015)
DOI:10.1038/NMAT4302

"Topological proximity effect in a topological insulator hybrid"
T. Shoman, A. Takayama, T. Sato, S. Souma, T. Takahashi, T. Oguchi, K. Segawa, and Y. Ando
Nature Communications 6, 6547-1-6 (Mar. 2015).
DOI: 10.1038/ncomms7547

"Fermiology of the Strongly Spin-Orbit Coupled Superconductor Sn_1-xIn_xTe: Implications for Topological Superconductivity"
T. Sato, Y. Tanaka, K. Nakayama, S. Souma, T. Takahashi, S. Sasaki, Z. Ren, A. A. Taskin, K. Segawa, and Y. Ando
Phys. Rev. Lett. 110, 206804-1-5 (May. 2013).
DOI: 10.1103/PhysRevLett.110.206804

"Experimental realization of a topologicalcrystalline insulator in SnTe"
Y. Tanaka, Z. Ren, T. Sato, K. Nakayama, S. Souma, T. Takahashi, K. Segawa, Y. Ando,
Nature Physics 8, 800–803 (Sep. 2012).
DOI: doi:10.1038/nphys2442

"Tunable Dirac cone in the topological insulatorBi_2-xSb_xTe_3-ySe_y"
T. Arakane, T. Sato, S. Souma, K. Kosaka, K. Nakayama, M. Komatsu, T. Takahashi, Zhi Ren, K. Segawa & Y. Ando,
Nature Communications 3, 636-1-5 (Jan. 2012).
DOI: 10.1038/ncomms1639

"Unexpected Mass Acquisition of Dirac Fermions at the Quantum Phase Transition of a Topological Insulator"
T. Sato, K. Segawa, K. Kosaka, S. Souma, K. Nakayama, K. Eto, T. Minami, Y. Ando, T. Takahashi,
Nature Physics 7, 840-844 (Aug. 2011).
DOI: 10.1038/nphys2058

"Direct evidence for Dirac-cone Topological Surface States in Ternary Chalcogenide TlBiSe₂"
T. Sato, K. Segawa, H. Guo, K. Sugawara, S. Souma, T. Takahashi and Yoichi Ando
Physical Review Letters 105, 136802-1-4 (2010).
DOI: http://dx.doi.org/10.1103/PhysRevLett.105.136802

"Band structure and Fermi surface of an extremely overdoped iron-based superconductor KFe₂As₂"
T. Sato, K. Nakayama, Y. Sekiba, P. Richard, Y.-M. Xu, S. Souma, T. Takahashi, G. F. Chen, J. L. Luo, N. L. Wang, and H. Ding
Physical Review Letters 103, 047002-1-4 (2009).
DOI: 10.1103/PhysRevLett.103.047002

"Fermi-surface-dependent superconducting gap in C6Ca"
K. Sugawara, T. Sato, and T. Takahashi
Nature Physics 5, 40-43 (2009).
DOI: 10.1038/nphys1128

"Observation of Band Renormalization Effects in Hole-Doped High-T_c Superconductors"
T. Sato, H. Matsui, T. Takahashi, H. Ding, H.-B. Yang, S.-C. Wang, T. Fujii, T. Watanabe, A. Matsuda, T. Terashima, and K. Kadowaki
Physical Review Letters 91, 157003-1-4 (2003).
DOI: 10.1103/PhysRevLett.91.157003

"Observation of dx2-y2-like superconducting gap in an electron-doped high-temperature superconductor"
T. Sato, T. Kamiyama, T. Takahashi, K. Kurahashi, and K. Yamada
Science 291, 1517-1519 (2001).
DOI: 10.1126/science.1058021