Superconductivity and a Mott Transition in a Hubbard Model on an Anisotropic Triangular Lattice

Abstract

A half-filled-band Hubbard model on an anisotropic triangular lattice (t in two bond directions and t' in the other) is studied using an optimization variational Monte Carlo method, to consider the Mott transition and superconductivity arising in κ-BEDT-TTF_2X. Adopting wave functions with doublon-holon binding factors, we reveal that a first-order Mott (conductor-to-nonmagnetic insulator) transition takes place at U=U_c approximately of the band width, for a wide range of t'/t. This transition is not directly connected to magnetism. Robust d-wave superconductivity appears in a restricted parameter range: immediately below U_c and moderate strength of frustration (0.4\lsim t'/t\lsim 0.7), where short-range antiferromagnetic correlation sufficiently develops but does not come to a long-range order. The relevance to experiments is also discussed.

15 pages, 17 figures, submitted to J. Phys. Soc. Jpn

References in corpus (4)

• Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor kappa-(ET)2Cu2(CN)3
• Comparison of the phase diagram of the half-filled layered organic superconductors with the phase diagram of the RVB theory of the Hubbard-Heisenberg model
• Universality Classes of Metal-Insulator Transitions in Strongly Correlated Electron Systems and Mechanism of High-Temperature Superconductivity
• Magnetism and superconductivity of strongly correlated electrons on the triangular lattice

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