A simple spin model for three steps relaxation and secondary proccesses in glass formers

TL;DR

This paper introduces a simple spin model that captures the complex relaxation and secondary processes observed in glass formers by simulating the competition between different cooperative behaviors.

Contribution

It presents a novel spin model combining two glassy components with tunable cooperativeness, reproducing secondary process phenomena without additional assumptions.

Findings

Model reproduces secondary process features in susceptibility spectra.

Captures trends under cooling and pressing conditions.

Demonstrates the role of cooperative competition in glassy dynamics.

Abstract

A number of general trends are known to occur in systems displaying secondary processes in glasses and glass formers. Universal features can be identified as components of large and small cooperativeness whose competition leads to excess wings or apart peaks in the susceptibility spectrum. To the aim of understanding such rich and complex phenomenology we analyze the behavior of a model combining two apart glassy components with a tunable different cooperativeness. The model salient feature is, indeed, based on the competition of the energetic contribution of groups of dynamically relevant variables, e.g., density fluctuations, interacting in small and large sets. We investigate how the model is able to reproduce the secondary processes physics without further ad hoc ingredients, displaying known trends and properties under cooling or pressing.