Liquid-liquid phase transition in nanoconfined Si-rich SiO2 liquids

Abstract

Molecular dynamics (MD) simulations have been performed to confirm the existence of liquid-liquid phase transition (LLPT) in nanoconfined Si-rich SiO2 liquid with different ratio of oxygen to silicon. The typical feature of the LLPT is layering transition which is induced by the change of slit size (SS) and pressure parallel to wall (P//). Abnormal shoulder peak between the first and second peaks in pair correlation function as a result of the change of SS and P// is another indication of the LLPTs. The structural evolution of the liquid layers during the LLPT is well explained by the change in angular correlation function. Moreover, the density, pressure perpendicular to walls, average potential energy and diffusion coefficient show abrupt change during the LLPT. LLPTs are similar in layering transition in different liquids but their appearances are not synchronous.