Size dependence of the phase transition temperature of metal nanocrystals

Abstract

Melting, freezing, and evaporation are common phase transition processes in metallic nanocrystals. Predicting these phase transitions and understanding their underlying mechanisms are crucial for the design, preparation, and application of nanomaterials. In this work, we establish the thermodynamic models to describe the size dependence of cohesive energy Ec, melting temperature Tm, freezing temperature Tf, and evaporation temperature Te. By comparing the predictions with the available experimental results, a good agreement is obtained. In addition, we find that at the same diameter D, the Tm(D)/Tm, Tf(D)/Tf, and Te(D)/Te of nanocrystals increase with the improvement of the ratio of solid-liquid interface energy γsl to interfacial stress f, indicating that γsl/f determines the thermal stability of the surfaces.