Interacting spinless fermions on the square lattice: Charge order, phase separation, and superconductivity

Article

关键词: NARROW ENERGY-BANDS;    METAL-SEMICONDUCTOR TRANSITION;    ELECTRON CORRELATIONS;    GREEN-FUNCTIONS;    MODEL;    EQUATIONS;    MOTION;   

DOI  :  10.1103/PhysRevB.104.155116

来源: SCIE

【 摘 要 】

We investigate the phase diagram of spinless fermions on a square lattice with nearest-neighbor interaction, using the recently developed projective truncation approximation in Green's function equation of motion. For attractive interaction, the ground state is in a homogeneous p + ip superconducting (SC) phase at high or low fermion densities. Near half filling is a phase separation (PS) between the SC phases. Allowing inhomogeneous solution, we obtain p-wave SC domains with positive interface energy. As temperature increases, the SC phases transit into normal phases above T-sc, generating a homogeneous normal phase (far away from n = 1/2), or a PS between normal phases with different densities (close to n = 1/2). Further increasing temperature to T-ps, the PS disappears and the particle-hole symmetry of the Hamiltonian is recovered. For repulsive interaction, depending on the filling, the ground state is in charge-ordered phase (half filling), charge-disordered phase (large hole/particle doping), or PS between them (weak doping). At finite temperature, the regime of charge order phase moves to finite V and extends to finite doping regime.

【 授权许可】

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