A Numerical Study of Phase Transitions Inside the Pores of Aerogels

TL;DR

This study models phase transitions within aerogel pores using a lattice-based Potts model and finite size scaling, revealing a change from first to second order transition with increasing density for q=4.

Contribution

It introduces a lattice-based Monte Carlo simulation approach to analyze how phase transition orders change inside aerogels based on density and q-values.

Findings

Transition changes from first to second order as density increases for q=4

Comparison shows weaker first order transition for q=3 in three dimensions

Correlated vs. non-correlated site occupation affects transition nature

Abstract

Phase transitions inside the pores of an aerogel are investigated by modelizing the aerogel structure by diffusion-limited cluster-cluster aggregation on a cubic lattice in a finite box and considering $q$-states Potts variables on the empty sites interacting via nearest-neighbours. Using a finite size scaling analysing of Monte-Carlo numerical results, it is concluded that for $q=4$ the transition changes from first order to second order as the aerogel concentration (density) increases. Comparison is made with the case $q=3$ (where the first order transition is weaker in three dimensions) and with the case $q=4$ but for randomly (non correlated) occupied sites. Possible applications to experiments are discussed.