Inexpensive discrete atomistic model technique for studying excitations on infinite disordered media: the case of orientational glass ArN$_2$

TL;DR

This paper presents a cost-effective discrete atomistic modeling technique for studying excitations in infinite disordered media, demonstrated on an argon-nitrogen glass system.

Contribution

It introduces a novel, computationally efficient method for simulating low-energy excitations in disordered systems using a spring-like atomic model with Monte Carlo sampling.

Findings

Successfully applied to ArN$_2$ solid solution

Allows simulation of large samples at low computational cost

Flexible to different interaction potentials

Abstract

Excitations of disordered systems such as glasses are of fundamental and practical interest but computationally very expensive to solve. Here we introduce a technique for modeling these excitations in an infinite disordered medium with a reasonable computational cost. The technique relies on a discrete atomic model to simulate the low-energy behavior of an atomic lattice with molecular impurities. The interaction between different atoms is approximated using a spring like interaction based on the Lennard Jones potential but can be easily adapted to other potentials. The technique allows to solve a statistically representative number of samples with a minimum of computational expense, and uses a Monte-Carlo approach to achieve a state corresponding to any given temperature. This technique has already been applied successfully to a problem with interest in condensed matter physics: the solid solution of N$_2$ in Ar.