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ID 117949
Author
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
Content Type
Journal Article
Description
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.
Journal Title
Physical Review B
ISSN
24699950
24699969
NCID
AA11187113
AA11734533
Publisher
American Physical Society
Volume
107
Issue
4
Start Page
045141
Published Date
2023-01-27
Rights
©2023 American Physical Society
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher
departments
Science and Technology