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ID 117949
著者
Mizokawa, T. Waseda University
Miki, K. Tokushima University
Matsui, Y. Tokushima University
Katayama, N. Nagoya University
Sawa, H. Nagoya University
Nohara, M. Hiroshima University
Lu, Y. Chongqing University
Takagi, H. University of Tokyo|Max Planck Institute for Solid State Research
Ikemoto, Y. Japan Synchrotron Radiation Research Institute
Moriwaki, T. Japan Synchrotron Radiation Research Institute
資料タイプ
学術雑誌論文
抄録
The layered chalcogenide Ta2NiSe5 has recently attracted much interest as a strong candidate for a long-sought excitonic insulator (EI). Since the physical properties of an EI are expected to depend sensitively on the external pressure (P), it is important to clarify the P evolution of a microscopic electronic state in Ta2NiSe5. Here we report the optical conductivity [σ (ω)] of Ta2NiSe5 measured at high P to 10 GPa and at low temperatures to 8 K. With cooling at P = 0, σ (ω) develops an energy gap of about 0.17 eV and a pronounced excitonic peak at 0.38 eV as reported previously. With increasing P, the energy gap becomes narrower and the excitonic peak is diminished. Above a structural transition at Ps ≃ 3 GPa, the energy gap becomes partially filled, indicating that Ta2NiSe5 is a semimetal after the EI state is suppressed by P. At higher P, σ (ω) exhibits metallic characteristics with no energy gap. The detailed P evolution of the energy gap and σ (ω) is presented, and discussed mainly in terms of a weakening of excitonic correlation with P.
掲載誌名
Physical Review B
ISSN
24699950
24699969
cat書誌ID
AA11187113
AA11734533
出版者
American Physical Society
107
4
開始ページ
045141
発行日
2023-01-27
権利情報
©2023 American Physical Society
EDB ID
出版社版DOI
出版社版URL
フルテキストファイル
言語
eng
著者版フラグ
出版社版
部局
理工学系