TY - JOUR
T1 - Superconductivity and a Mott transition in a Hubbard model on an anisotropic triangular lattice
AU - Watanabe, Tsutomu
AU - Yokoyama, Hisatoshi
AU - Tanaka, Yukio
AU - Inoue, Jun ichiro
N1 - Funding Information:
This work is partly supported by Grant-in-Aid from the Ministry of Education, etc. Japan, from the Supercomputer Center, ISSP, Univ. of Tokyo, from NAREGI Nanoscience Project and for the 21st Century COE “Frontiers of Computational Science”.
PY - 2006/10/1
Y1 - 2006/10/1
N2 - With a mind to a Mott transition and superconductivity (SC) arising in κ-(BEDT-TTF)2X, we study a half-filled-band Hubbard model on an anisotropic triangular lattice (t in two bond directions and t′ in the other). Using an optimization variational Monte Carlo method, we find that with doublon-holon binding factors in the trial functions, a first-order Mott transition takes place at U = Uc approximately of the band width. For a moderate frustration (t′/t = 0.4), the d-wave superconducting correlation Pd is sizably enhanced just under Uc/t, whereas for a strong frustration (t′/t = 0.8), Pd is hardly enhanced for any value of U/t. Since the behavior of Pd is closely connected to that of the spin structure factor S(π, π), the SC in this model must be induced by the antiferromagnetic correlation.
AB - With a mind to a Mott transition and superconductivity (SC) arising in κ-(BEDT-TTF)2X, we study a half-filled-band Hubbard model on an anisotropic triangular lattice (t in two bond directions and t′ in the other). Using an optimization variational Monte Carlo method, we find that with doublon-holon binding factors in the trial functions, a first-order Mott transition takes place at U = Uc approximately of the band width. For a moderate frustration (t′/t = 0.4), the d-wave superconducting correlation Pd is sizably enhanced just under Uc/t, whereas for a strong frustration (t′/t = 0.8), Pd is hardly enhanced for any value of U/t. Since the behavior of Pd is closely connected to that of the spin structure factor S(π, π), the SC in this model must be induced by the antiferromagnetic correlation.
KW - Anisotropic triangular lattice
KW - Hubbard model
KW - Mott transition
KW - Variational Monte Carlo method
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U2 - 10.1016/j.physc.2006.03.107
DO - 10.1016/j.physc.2006.03.107
M3 - Article
AN - SCOPUS:33748168300
VL - 445-448
SP - 166
EP - 170
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 1-2
ER -