Nonequilibrium relaxation and aging scaling of the Coulomb and Bose glass

Abstract

We employ Monte Carlo simulations to investigate the nonequilibrium relaxation properties of the two- and three-dimensional Coulomb glass with different long-range repulsive interactions. Specifically, we explore the aging scaling laws in the two-time density autocorrelation function. We find that, in the time window and parameter range accessible to us, the scaling exponents are not universal, depending on the filling fraction and temperature: As either the temperature decreases or the filling fraction deviates more from half filling, the exponents reflect markedly slower relaxation kinetics. In comparison with a repulsive Coulomb potential, appropriate for impurity states in strongly disordered semiconductors, we observe that, for logarithmic interactions, the soft pseudogap in the density of states is considerably broader, and the dependence of the scaling exponents on external parameters is much weaker. The latter situation is relevant for flux creep in the disorder-dominated Bose glass phase of type-II superconductors subject to columnar pinning centers.

Structural relaxation and aging scaling in the Coulomb and Bose glass models

“…Including random on-site energies from a flat distribution into the Coulomb and Bose glass models causes their re-laxation to become faster. This change in the aging scaling exponents implies that these exponents are not universal and in fact depend on various microscopic system parameters [29,30].…”

“…The three-dimensional system was observed in Refs. [29,30] to display a faster total suppression of the Coulomb gap than the two-dimensional system. Fig.…”

“…Previous studies addressed the Coulomb gap and nonequilibrium relaxation properties under random initial conditions [9,10,29,30]. It is worthwhile to analyze the effect of abrupt changes in the density of charge carriers in the Coulomb glass model or analogously flux lines in type-II superconductors with linear defects on the Coulomb gap's properties and aging scaling exponents to probe the system's sensitivity to sudden changes in parameters.…”

“…Analogous to the Coulomb glass, the Bose glass is composed of long-range interacting "particles" and spatial disorder, and hence this model's density of states was confirmed to similarly display a soft gap [27,28], and the nonequilibrium relaxation dynamics display rich aging and scaling properties [29,30]. Numerical and analytical studies by Somoza et al investigated the density of states of two-dimensional systems with logarithmic interactions at zero and finite temperatures [31].…”

Aging phenomena in the two-dimensional complex Ginzburg-Landau equation

“…Aging phenomena have been established to exist in a broad variety of physical systems [4], which range, e.g., from simple Ising ferromagnetics [6][7][8], isotropic antiferromagnets [9], disordered magnets [10], spin glasses [11], disordered electronic Coulomb glass systems [12][13][14], magnetic flux lines in type-II superconductors [15][16][17][18][19][20][21][22], disordered semiconductors [23,24], and skyrmion topological defects [25,26] to driven lattice gases [27,28], population dynamics models [29], and driven-dissipative Bose-Einstein condensation [30]. We remark that most of the above investigations utilized Monte Carlo or molecular dynamics computer simulations.…”