Benchmark of a modified iterated perturbation theory approach on the fcc lattice at strong coupling

Article

关键词: ELECTRONIC-STRUCTURE CALCULATIONS;    MEAN-FIELD THEORY;    HUBBARD-MODEL;    ANDERSON MODEL;    SELF-ENERGY;    SYSTEMS;    TRANSITION;    TRANSPORT;   

DOI  :  10.1103/PhysRevB.86.085133

来源: SCIE

【 摘 要 】

The dynamical mean-field theory approach to the Hubbard model requires a method to solve the problem of a quantum impurity in a bath of noninteracting electrons. Iterated perturbation theory (IPT) has proven its effectiveness as a solver in many cases of interest. Based on general principles and on comparisons with an essentially exact continuous-time quantum Monte Carlo (CTQMC) solver, here we show that the standard implementation of IPT fails away from half-fillingwhen the interaction strength is much larger than the bandwidth. We propose a slight modification to the IPT algorithm that replaces one of the equations by the requirement that double occupancy calculated with IPT gives the correct value. We call this method IPT-D. We recover the Fermi liquid ground state away from half-filling. The Fermi liquid parameters, density of states, chemical potential, energy, and specific heat on the fcc lattice are calculated with both IPT-D and CTQMC as benchmark examples. We also calculated the resistivity and the optical conductivity within IPT-D. Particle-hole asymmetry persists even at coupling twice the bandwidth. A generalization to the multiorbital case is suggested. Several algorithms that speed up the calculations are described in appendixes.

【 授权许可】

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