Critical behavior of the Coulomb-glass model in the zero-disorder limit: Ising universality in a system with long-range interactions

TL;DR

This study investigates the critical behavior of the Coulomb-glass model with long-range interactions, finding that it exhibits Ising universality class critical exponents in two and three dimensions, similar to short-range models.

Contribution

It demonstrates that the Coulomb-glass model with long-range interactions shares the same universality class as the short-range Ising model in 2D and 3D, using finite-size scaling analysis.

Findings

Continuous phase transitions in 2D and 3D systems.

Critical exponents match those of the short-range Ising model.

One-dimensional susceptibility shows singular behavior at zero temperature.

Abstract

The ordering of charges on half-filled hypercubic lattices is investigated numerically, where electroneutrality is ensured by background charges. This system is equivalent to the $s = 1/2$ Ising lattice model with antiferromagnetic $1/r$ interaction. The temperature dependences of specific heat, mean staggered occupation, and of a generalized susceptibility indicate continuous order-disorder phase transitions at finite temperatures in two- and three-dimensional systems. In contrast, the susceptibility of the one-dimensional system exhibits singular behavior at vanishing temperature. For the two- and three-dimensional cases, the critical exponents are obtained by means of a finite-size scaling analysis. Their values are consistent with those of the Ising model with short-range interaction, and they imply that the studied model cannot belong to any other known universality class. Samples of up to 1400, $112^2$, and $22^3$ sites are considered for dimensions 1 to 3, respectively.