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

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.