2019/01/18 by Kazuhiro Seki, Yuichi Otsuka, Seiji Yunoki +1 · 11 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Dirac fermion #Fermi energy #Fermi liquid theory #Fermion #Ground state #Hubbard model #Massless particle #Mathematics #Monte Carlo method #Physics #Physics of Superconductivity and Magnetism #Quantum Monte Carlo #Quantum mechanics #Quasiparticle #Superconductivity in MgB2 and Alloys #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.99.125145
published in Physical review. B./Physical review. B 99(12) (American Physical Society) · 10 pages, 6 figures
arxiv created 2019/01/18 · openalex created_date 2019/01/25 · openalex publication_date 2019/03/25 · arxiv updated 2019/04/03 · openalex updated_date 2026/08/05
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 (\ensuremath∼r^\ensuremath-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.