Liu Yizhi, Sun Gang, Xu Limei
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
School of Chemistry, University of Sydney, Sydney, New South Wales, Australia.
J Chem Phys. 2021 Apr 7;154(13):134503. doi: 10.1063/5.0038058.
Using the potential energy landscape (PEL) formalism and molecular dynamics simulations, we investigate a phase transformation between two amorphous solid states of gallium, namely, a low-density amorphous solid (LDA) and a high-density amorphous solid (HDA), and compare with its equilibrium counterpart, the liquid-liquid phase transition (LLPT). It is found that on the PEL, the signatures of the out-of-equilibrium LDA-HDA transition are reminiscent of those of the equilibrium LLPT in terms of pressure, inherent structure pressure, inherent structure energy, and shape function, indicating that the LDA-HDA transformation is a first-order-like transition. However, differences are also found between the out-of-equilibrium phase transition and the equilibrium one, for example, the path from LDA to HDA on the PEL cannot be accessed by the path from LDL to HDL. Our results also suggest that the signatures of the out-of-equilibrium transition in gallium are rather general features of systems with an accessible LLPT-not only systems with pairwise interactions but also those with many-body interactions. This finding is of crucial importance for obtaining a deeper understanding of the nature of transitions in the polyamorphic family.
利用势能面（PEL）形式理论和分子动力学模拟，我们研究了镓的两种非晶态固体之间的相变，即低密度非晶态固体（LDA）和高密度非晶态固体（HDA），并将其与平衡态的对应相变，即液 - 液相转变（LLPT）进行比较。研究发现，在势能面上，非平衡态的LDA - HDA转变在压力、固有结构压力、固有结构能量和形状函数方面的特征让人联想到平衡态的LLPT，这表明LDA - HDA转变是一种类似一级相变的转变。然而，非平衡相变和平衡相变之间也存在差异，例如，势能面上从LDA到HDA的路径无法通过从LDL到HDL的路径实现。我们的结果还表明，镓中非平衡转变的特征是具有可及LLPT的系统的相当普遍的特征——不仅是具有成对相互作用的系统，还有具有多体相互作用的系统。这一发现对于更深入理解多晶型家族中转变的本质至关重要。
