Jin Lei, Shi Yin, Allen Frances I, Chen Long-Qing, Wu Junqiao
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2022 Dec 9;129(24):245701. doi: 10.1103/PhysRevLett.129.245701.
In a first-order phase transition, critical nucleus size governs nucleation kinetics, but the direct experimental test of the theory and determination of the critical nucleation size have been achieved only recently in the case of ice formation in supercooled water. The widely known metal-insulator phase transition (MIT) in strongly correlated VO_{2} is a first-order electronic phase transition coupled with a solid-solid structural transformation. It is unclear whether classical nucleation theory applies in such a complex case. In this Letter, we directly measure the critical nucleus size of the MIT by introducing size-controlled nanoscale nucleation seeds with focused ion irradiation at the surface of a deeply supercooled metal phase of VO_{2}. The results compare favorably with classical nucleation theory and are further explained by phase-field modeling. This Letter validates the application of classical nucleation theory as a parametrizable model to describe phase transitions of strongly correlated electron materials.
在一级相变中，临界核尺寸决定成核动力学，但直到最近，在过冷水结冰的情况下才实现了该理论的直接实验验证以及临界成核尺寸的测定。在强关联的VO₂中广为人知的金属 - 绝缘体相变（MIT）是一种与固 - 固结构转变耦合的一级电子相变。目前尚不清楚经典成核理论是否适用于这种复杂情况。在本信函中，我们通过聚焦离子束辐照在深度过冷的VO₂金属相表面引入尺寸可控的纳米级成核种子，直接测量了MIT的临界核尺寸。结果与经典成核理论吻合良好，并通过相场模型得到进一步解释。本信函验证了经典成核理论作为一种可参数化模型在描述强关联电子材料相变方面的应用。
