First-principles calculations of monolayer hexagonal boron nitride: Possibility of superconductivity

Based on density-functional first-principles calculations and the Wannier interpolation technique, we have investigated the electron-phonon coupling (EPC) in hole-doped monolayer hexagonal boron nitride (h-BN). We align the Fermi level to a Van Hove singularity by 0.4 holes/cell doping, the largest hole concentration that can be realized in monolayer h-BN. Under this doping level, the EPC for free-standing monolayer h-BN is weak. However, biaxial tensile strain can enhance the EPC significantly. We predict that monolayer h-BN can become a phonon-mediated superconductor by the synergic effects of hole doping and biaxial tensile strain, with transition temperature exceeding 40 K.