Abstract
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.
| Original language | English |
|---|---|
| Article number | 205135 |
| Journal | Physical Review B - Condensed Matter and Materials Physics |
| Volume | 91 |
| Issue number | 20 |
| DOIs | |
| Publication status | Published - 2015 May 26 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials
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Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1T- TiSe2 : A variational Monte Carlo study. / Watanabe, Hiroshi; Seki, Kazuhiro; Yunoki, Seiji.
In: Physical Review B - Condensed Matter and Materials Physics, Vol. 91, No. 20, 205135, 26.05.2015.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Charge-density wave induced by combined electron-electron and electron-phonon interactions in 1T- TiSe2
T2 - A variational Monte Carlo study
AU - Watanabe, Hiroshi
AU - Seki, Kazuhiro
AU - Yunoki, Seiji
PY - 2015/5/26
Y1 - 2015/5/26
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.91.205135
DO - 10.1103/PhysRevB.91.205135
M3 - Article
AN - SCOPUS:84930210369
VL - 91
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 0163-1829
IS - 20
M1 - 205135
ER -