ID | 117949 |
Author |
Okamura, Hidekazu
Tokushima University
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Mizokawa, T.
Waseda University
Miki, K.
Tokushima University
Matsui, Y.
Tokushima University
Noguchi, Naoki
Tokushima University
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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
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Content Type |
Journal Article
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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.
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Journal Title |
Physical Review B
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ISSN | 24699950
24699969
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NCID | AA11187113
AA11734533
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Publisher | American Physical Society
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Volume | 107
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Issue | 4
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Start Page | 045141
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Published Date | 2023-01-27
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Rights | ©2023 American Physical Society
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EDB ID | |
DOI (Published Version) | |
URL ( Publisher's Version ) | |
FullText File | |
language |
eng
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TextVersion |
Publisher
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departments |
Science and Technology
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