Electric field and strain tunable electronic structures in monolayer Black Phosphorus

Electric field or in-plane strain is used to tailor the electronic structures of monolayer Black Phosphorus (M-BP). Upon applying electric field, the band gap of M-BP is greatly reduced and insulator-metal transition happens under certain field intensity. The electric field impact on the electron effective mass (EEM) of M-BP is anisotropic. The EEM along armchair direction is increased and that in the zigzag direction is greatly reduced. Tensile strain under small magnitude enlarges the band gap of M-BP and starts to reduce it when the strain becomes relatively large. The anisotropic EEM in the M-BP can also be reversed by the tensile strain. Under tensile strain, the electronic structure of M-BP becomes to be more efficiently modulated by the electric field. Compression strain only reduces the band gap of M-BP and has little impact on the EEM. For the M-BP under compression strain, its electronic structure can hardly be altered by the electric field.