Huang Shenyang, Lu Yang, Wang Fanjie, Lei Yuchen, Song Chaoyu, Zhang Jiasheng, Xing Qiaoxia, Wang Chong, Xie Yuangang, Mu Lei, Zhang Guowei, Yan Hao, Chen Bin, Yan Hugen
State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonic Structures (Ministry of Education), and Department of Physics, Fudan University, Shanghai 200433, China.
Center for High Pressure Science & Technology Advanced Research, Shanghai 201203, China.
Phys Rev Lett. 2021 Oct 29;127(18):186401. doi: 10.1103/PhysRevLett.127.186401.
Through infrared spectroscopy, we systematically study the pressure effect on electronic structures of few-layer black phosphorus (BP) with layer number ranging from 2 to 13. We reveal that the pressure-induced shift of optical transitions exhibits strong layer dependence. In sharp contrast to the bulk counterpart which undergoes a semiconductor to semimetal transition under ∼1.8 GPa, the band gap of 2 L increases with increasing pressure until beyond 2 GPa. Meanwhile, for a sample with a given layer number, the pressure-induced shift also differs for transitions with different indices. Through the tight-binding model in conjunction with a Morse potential for the interlayer coupling, this layer- and transition-index-dependent pressure effect can be fully accounted. Our study paves a way for versatile van der Waals engineering of two-dimensional BP.
通过红外光谱，我们系统地研究了层数在2到13之间的少层黑磷（BP）的电子结构的压力效应。我们发现，压力诱导的光学跃迁位移表现出强烈的层数依赖性。与在约1.8 GPa下从半导体转变为半金属的体相材料形成鲜明对比的是，2层BP的带隙随压力增加而增大，直至超过2 GPa。同时，对于给定层数的样品，压力诱导的位移对于不同指数的跃迁也有所不同。通过结合层间耦合的莫尔斯势的紧束缚模型，可以充分解释这种依赖于层数和跃迁指数的压力效应。我们的研究为二维BP的多功能范德华工程铺平了道路。
