The strain effect on superconductivity in phosphorene: a first-principles prediction

The effects of biaxial and uniaxial strains on electron-phonon coupling and superconductivity in monolayer phosphorene are systematically investigated by first-principles calculations. It is found that the electron-phonon coupling primarily comes from the low frequency optical phonon modes around B-3g(1), and the biaxial strain gives rise to more a obvious increase in density of states around the Fermi level and phonon softening in the low frequency regime compared to the other two types of uniaxial strain. Therefore, the electron-phonon coupling is more significantly enhanced by the biaxial strain than the uniaxial strains and the superconducting transition temperature T-c increases sharply from 3 K to 16 K at the typical doping concentration n(2D) = 3.0 x 10(14) cm(-2) when the biaxial strain reaches 4.0%.