Constrained-path quantum Monte Carlo simulations of the zero-temperature disordered two-dimensional Hubbard model

Article

关键词: METAL-INSULATOR-TRANSITION;    PAIRING CORRELATIONS;    PHASE-SEPARATION;    GROUND-STATE;    FIELD THEORY;    ORDER;    SUPERCONDUCTIVITY;    B=0;   

DOI  :  10.1103/PhysRevB.64.184402

来源: SCIE

【 摘 要 】

We study the effects of disorder on long-range antiferromagnetic correlations in the half-filled, two-dimensional, repulsive Hubbard model at T = 0. A mean field approach is first employed to gain a qualitative picture of the physics and to guide our choice for a trial wave function in a constrained path quantum Monte Carlo (CPQMC) method that allows for a more accurate treatment of correlations. Within the mean field calculation, we observe both Anderson and Mott insulating antiferromagnetic phases. There are transitions to a paramagnet only for relatively weak coupling, U < 2t in the case of bond disorder, and U < 4t in the case of on-site disorder. Using ground-state CPQMC we demonstrate that this mean field approach significantly overestimates magnetic order. For U = 4t, we find a critical bond disorder of V-c approximate to (1.6 +/- 0.4)t even though within mean field theory no paramagnetic phase is found for this value of the interaction. In the site disordered case. we find a critical disorder of V-c approximate to (5.0 +/- 0.5)t at U = 4t.

【 授权许可】

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