Spin Glass in the Bond-Diluted J1-J2 Ising Model on the Square Lattice

TL;DR

This study uses Monte Carlo simulations with parallel tempering to explore the phase diagram of a 2D bond-diluted frustrated Ising model, revealing a spin-glass phase influenced by disorder and frustration, with implications for iron-based superconductors.

Contribution

It introduces a detailed phase diagram of the bond-diluted J1-J2 Ising model on a square lattice using advanced Monte Carlo methods, highlighting the spin-glass phase and dynamic exponents.

Findings

Identification of a spin-glass phase between stripe and Neel phases.

Ground-state energy and EA order parameter scaling with system size.

Different dynamic exponents z_E and z_q for the spin glass phase.

Abstract

We use Monte Carlo (MC) methods to simulate a two-dimensional (2D) bond-diluted Ising model on the square lattice which has frustration between the nearest-neighbor interaction J1 and the next-nearest-neighbor interaction J2. In this paper, we use the parallel tempering algorithm to study the thermodynamics for different diluted ratio x and give the phase diagram. The presence of both frustration and disorder results in a spin-glass phase, which exists between the stripe antiferromagnetic phase and the Neel phase. We present the ground-state energy of T -> 0 and the size-dependence of Edwards-Anderson (EA) order parameter for the spin glass phase. By scaling the mean energy and the EA order parameter from the simulated annealing with the Kibble-Zurek (KZ) mechanism, we obtain two different dynamic exponents z_E and z_q for the spin glass phase. Experimentally, this model has close implication with the FeAs plane of the iron-based superconductor BaFe2(As(1-x)P(x))2, where a spin-glass like phase was found.