Electron–Hole Excitation Induced Softening in Boron Carbide-Based Superhard Materials
Electron–Hole Excitation Induced Softening in Boron Carbide-Based Superhard Materials
复制标题
碳化硼基超硬材料中电子空穴激发引起的软化
DOI：
10.1021/acsami.2c05528
复制
发表时间：
2022
影响因子：
9.5
通讯作者：
An, Qi
中科院分区：
文献类型：
--
作者：
He, Yi;Shen, Yidi;Tang, Bin;An, Qi
半导体中的光机械效应是指光致电子空穴（e-h）激发影响塑性变形的现象。迄今为止，已经进行了越来越多的理论和实验研究来说明这种现象的物理起源。相比之下，关于超硬材料中这种效应的讨论却很少。在这里，我们采用约束密度泛函理论模拟来评估 e-h 激发如何影响两种硼基超硬材料：碳化硼 (B4C) 和次磷化硼 (B12P2)。我们发现两个系统的理想剪切强度在 e-h 激发态下都会降低。在电子激发下，电子和空穴的重新分布导致强度降低，削弱了剪切变形下最初断裂的键。模拟结果为超硬材料在e-h激励下的软化效应提供了基本解释。这项研究还为通过光照射调节超硬材料的机械性能提供了基础。
Photomechanical effect in semiconductors refers to a phenomenon that plastic deformation is influenced by light-induced electron–hole (e-h) excitation. To date, increasing amounts of theoretical and experimental studies have been performed to illustrate the physical origin of this phenomenon. In contrast, there has been little discussion about this effect in superhard materials. Here, we adopted constrained density functional theory simulations to assess how e-h excitation influences two boron-based superhard materials: boron carbide (B4C) and boron subphosphide (B12P2). We found that the ideal shear strengths of both systems decrease under e-h excited states. Under e-h excitation, the redistribution of electrons and holes contributes to the decreased strength, weakening the bonds initially broken under the shear deformation. The simulation results provide a fundamental explanation for the softening effects of superhard materials under e-h excitation. This study also provides a basis to tune the mechanical properties of superhard materials via light irradiation.