Fermi-liquid ground state of interacting Dirac fermions in two dimensions

Article

关键词: ELECTRON-ELECTRON INTERACTIONS;    FINITE-TEMPERATURE PROPERTIES;    HUBBARD-MODEL;    EQUILIBRIUM PROPERTIES;    LANDAU THEORY;    MONTE-CARLO;    TRANSITION;    FERROMAGNETISM;    DERIVATION;    EXPANSION;   

DOI  :  10.1103/PhysRevB.99.125145

来源: SCIE

【 摘 要 】

An unbiased zero-temperature auxiliary-field quantum Monte Carlo method is employed to analyze the nature of the semimetallic phase of the two-dimensional Hubbard model on the honeycomb lattice at half filling. It is shown that the quasiparticle weight Z of the massless Dirac fermions at the Fermi level, which characterizes the coherence of zero-energy single-particle excitations, can be evaluated in terms of the long-distance equal-time single-particle Green's function. If this quantity remains finite in the thermodynamic limit, the low-energy single-particle excitations of the correlated semimetallic phase are described by a Fermi-liquid-type single-particle Green's function. Based on the unprecedentedly large-scale numerical simulations on finite-size clusters containing more than 10 000 sites, we show that the quasiparticle weight remains finite in the semimetallic phase below a critical interaction strength. This is also supported by the long-distance algebraic behavior (similar to r(-2), where r is distance) of the equal-time single-particle Green's function that is expected for the Fermi liquid. Our result thus provides a numerical confirmation of Fermi-liquid theory in two-dimensional correlated metals.

【 授权许可】

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