Finite-size effects in transport data from Quantum Monte Carlo simulations

Abstract

We have examined the behavior of the compressibility, the dc-conductivity, the single-particle gap, and the Drude weight as probes of the density-driven metal-insulator transition in the Hubbard model on a square lattice. These quantities have been obtained through determinantal quantum Monte Carlo simulations at finite temperatures on lattices up to 16 X 16 sites. While the compressibility, the dc-conductivity, and the gap are known to suffer from `closed-shell' effects due to the presence of artificial gaps in the spectrum (caused by the finiteness of the lattices), we have established that the former tracks the average sign of the fermionic determinant (<sign>), and that a shortcut often used to calculate the conductivity may neglect important corrections. Our systematic analyses also show that, by contrast, the Drude weight is not too sensitive to finite-size effects, being much more reliable as a probe to the insulating state. We have also investigated the influence of the discrete imaginary-time interval (Δτ) on <sign>, on the average density (ρ), and on the double occupancy (d): we have found that <sign> and ρare more strongly dependent on Δτaway from closed-shell configurations, but d follows the Δτ^2 dependence in both closed- and open-shell cases.

11 pages and 16 figures. To appear in Phys Rev B

References in corpus (10)

• Computational complexity and fundamental limitations to fermionic quantum Monte Carlo simulations
• Quantum spin-liquid emerging in two-dimensional correlated Dirac fermions
• Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition
• Spatially inhomogeneous phase in the two-dimensional repulsive Hubbard model
• Using the average spectrum method to extract dynamics from quantum Monte Carlo simulations
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• Finite Drude weight for 1D low temperature conductors
• Interacting lattice electrons with disorder in two dimensions: Numerical evidence for a metal-insulator transition with a universal critical conductivity
• Magnetic properties of interacting, disordered electron systems in d=2 dimensions

Cited by in corpus (20)

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• Thermodynamics of correlated electrons in a magnetic field
• Dynamical resilience to disorder: the dilute Hubbard model on the Lieb lattice
• Magnetism, transport, and thermodynamics in two-dimensional half-filled Hubbard superlattices
• Determinant Quantum Monte Carlo Study of Exhaustion in the Periodic Anderson Model
• Inducing a metal-insulator transition in disordered interacting Dirac fermion systems via an external magnetic field
• Doping-dependent metal-insulator transition in a disordered Hubbard model
• Size and shape of Mott regions for fermionic atoms in a two-dimensional optical lattice
• Metal-insulator transition in the disordered Hubbard model of the Lieb lattice
• Defining a universal sign to strictly probe a phase transition
• Effects of lattice geometry on thermopower properties of the repulsive Hubbard model
• Flat bands and superconductivity induced by periodic strain in monolayer graphene
• Comparison of superconducting pairing in doped cuprates and nickelates within an extended Hubbard model
• An intermediate phase induced by dilution in a correlated Dirac Fermi system
• Critical behavior of itinerant fermions - role of finite size effects
• Transport anisotropy and metal-insulator transition in striped Dirac fermion systems
• Magnetic phase transition in disordered interacting Dirac fermion systems via the Zeeman field
• Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping