Strain Tuning of the Electronic Structures of Few-Layer Black Phosphorus

Black phosphorus(BP) is a Van Der Waals material consisted of puckered atomic layers coupled together by the weak Van Der Waals force. Although Van Der Waals force is weak, it plays an important role in their bandstructure evolution. In this work, we tune the bandstructures of few-layer (2-10layer) black phosphorus by applying in-plane biaxial strain. A large tunability has been observed for all of the few-layer BP samples. Careful examination reveals that the strain effect has layer dependence and transition order dependence, which can be accounted by the interlayer coupling effect. Meanwhile, Raman studies for the strained BP have been performed as well, which corroborate our observations.