| Abstract Scope |
Photomechanical effects have been known for decades, while the underlying mechanism remains not fully understood. Here, we employed advanced quantum mechanics (QM) simulations to investigate how the excited e-h pairs affect the deformation and failures in several typical semiconductors: ionic crystal ZnS, covalent crystal GaP and superhard boron carbide (B4C). We found that in ZnS the dislocation dominated deformation mode transforms to a twin dominated deformation mode when the electron-hole pair are excited, leading to a brittle failure. While the dislocation dominated mechanism leads to a ductile mechanical behavior under the ground state. For covalent GaP, we found that the energy barrier for deformation slip in GaP is significantly reduced by generating high-concentration EHPs, exhibiting metal-like ductility. For superstrong B4C, the excited e-h pairs affect the deformation mechanism leading to amorphous band formation. Our results provide the theoretical basis to investigate the photon-mechanical behaviors of semiconductors. |