报告题目 (Title)：Quantum Color Centers in Few-Layer h-BN（少层六方氮化硼h-BN中的量子色心）

报告人 (Speaker)：贾帆豪 特聘副教授（杭州电子科技大学）

报告时间 (Time)：2023年12月18日(周一) 10:30

报告地点 (Place)：校本部 E106

邀请人 (Inviter)：任伟 教授

主办部门：理学院物理系

摘要 (Abstract)：

Color centers with deep-level states in the wide-gap h-BN monolayer have great potential applications in quantum devices. We have performed first-principles calculations to investigate the coupling effects between structural, electronic, and vibrational properties of the CBVN and NBVN color centers in the h-BN monolayer. Their ground-state structure can be planar or out-of-plane distorted, depending on the occupations of defect states. This talk will focus on the impact of the out-of-plane displacement and revealed its origin by analyzing the chemical bonding features of the defect states and the pseudo Jahn-Teller (PJT) effect of electron-phonon coupling. Although the out-of-plane displacements do not significantly change the vibrational set, these distinct quasi-local phonons suggested by local vibrational analysis can still be used as fingerprints to support experimental studies to identify specific point defects. We then extend our interest to the few-layer h-BN where the layered structure itself introduces a complex set of combined effects, including quantum confinement effects of different layer thicknesses, local symmetries of specific stacking orders, and varying electron-phonon coupling due to certain local displacements. These findings will deepen the understanding of quantum color center systems using few-layer van der Waals materials.