Atomistic insights into the enhanced stability and phase change speed of Al-Sb phase change materials

In this work, ab-initio molecular dynamics simulations were performed for Al-Sb system with and without excessive Al. Our results demonstrated the population of low angle bond is apparently increased due to the addition of excessive Al. The necessary bond transition from low angle to high angle in crystallization process was significantly retarded, which might be the origin of enhanced thermal stability of AlSb with excessive Al. The weak Al-Sb bond in the low Al-Sb-Al bond angle accounts for the fast phase change speed of Al-Sb system. Our work clarified the physical origin of the superior properties of Al-Sb system at the atomic scale and provided some new insights toward PCMs design.