A material potentially exhibiting multiple crystalline phases with distinct optoelectronic properties can serve as a phase-change memory material. The sensitivity and kinetics can be enhanced when the two competing phases have large electronic structure contrast and the phase change process is diffusionless and martensitic. In this work, we theoretically and computationally illustrate that such a phase transition could occur in the group-IV monochalcogenide SnSe compound, which can exist in the quantum topologically trivial Pnma-SnSe and nontrivial \(Fm\bar 3m\)-SnSe phases. Furthermore, owing to the electronic band structure differences of these phases, a large contrast in the optical responses in the THz region is revealed. According to the thermodynamic theory for a driven dielectric medium, optomechanical control to trigger a topological phase transition using a linearly polarized laser with selected frequency, power and pulse duration is proposed. We further estimate the critical optical electric field to drive a barrierless transition that can occur on the picosecond timescale. This light actuation strategy does not require fabrication of mechanical contacts or electrical leads and only requires transparency. We predict that an optically driven phase transition accompanied by a large entropy difference can be used in an “optocaloric” cooling device.

潜在地呈现具有不同光电特性的多个结晶相的材料可以用作相变存储材料。当两个竞争相具有较大的电子结构对比并且相变过程为无扩散和马氏体时，可以提高灵敏度和动力学。在这项工作中，我们在理论上和计算上说明了这样的相变可能发生在IV型单硫族化物SnSe化合物中，该化合物可以存在于量子拓扑琐碎的Pnma -SnSe和非琐碎的\（Fm \ bar 3m \）中-SnSe相。此外，由于这些相位的电子带结构差异，显示出在THz区域中的光学响应中的大反差。根据对驱动介质的热力学理论，提出了一种光机械控制方法，该方法采用线性偏振激光器选择频率，功率和脉冲持续时间来触发拓扑相变。我们进一步估计了临界光电场，以驱动可能发生在皮秒时间尺度上的无障碍过渡。这种光致动策略不需要机械触点或电引线的制造，而仅需要透明性。我们预测，在“光热”冷却装置中可以使用伴随着大的熵差的光学驱动相变。