Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1T- TiSe2: A variational Monte Carlo study

Hiroshi Watanabe, Kazuhiro Seki, Seiji Yunoki

研究成果: Article査読

33 被引用数 (Scopus)

抄録

To clarify the origin of a charge-density wave (CDW) phase in 1T-TiSe2, we study the ground-state property of a half-filled two-band Hubbard model in a triangular lattice including electron-phonon interaction. By using the variational Monte Carlo method, the electronic and lattice degrees of freedom are both treated quantum mechanically on an equal footing beyond the mean-field approximation. We find that the cooperation between Coulomb interaction and electron-phonon interaction is essential to induce the CDW phase. We show that the "pure" exciton condensation without lattice distortion is difficult to realize under the poor nesting condition of the underlying Fermi surface. Furthermore, by systematically calculating the momentum-resolved hybridization between the two bands, we examine the character of electron-hole pairing from the viewpoint of BCS-BEC crossover within the CDW phase and find that the strong-coupling BEC-like pairing dominates. We therefore propose that the CDW phase observed in 1T-TiSe2 originates from a BEC-like electron-hole pairing.

本文言語English
論文番号205135
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
91
20
DOI
出版ステータスPublished - 2015 5月 26
外部発表はい

ASJC Scopus subject areas

  • 凝縮系物理学
  • 電子材料、光学材料、および磁性材料

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