Details

Autor(en) / Beteiligte

• Wakisaka, Y
• Sudayama, T
• Takubo, K
• Mizokawa, T
• Arita, M
• Namatame, H
• Taniguchi, M
• Katayama, N
• Nohara, M
• Takagi, H

Titel

Excitonic insulator state in Ta2NiSe5 probed by photoemission spectroscopy

Ist Teil von

• Physical review letters, 2009-07, Vol.103 (2), p.026402-026402

Ort / Verlag

United States

Erscheinungsjahr

2009

Quelle

APS - PROLA

Beschreibungen/Notizen

• We report on a photoemission study of Ta2NiSe5 that has a quasi-one-dimensional structure and an insulating ground state. Ni 2p core-level spectra show that the Ni 3d subshell is partially occupied and the Ni 3d states are heavily hybridized with the Se 4p states. In angle-resolved photoemission spectra, the valence-band top is found to be extremely flat, indicating that the ground state can be viewed as an excitonic insulator state between the Ni 3d-Se 4p hole and the Ta 5d electron. We argue that the high atomic polarizability of Se plays an important role to stabilize the excitonic state.