Phonon-mediated superconductivity near the lattice instability in hole-doped hydrogenated monolayer hexagonal boron nitride

Employing the density functional theory with local density approximation, we show that the fully hydrogenated monolayer-hexagonal boron nitride (H2BN) has a direct band gap of 2.96 eV in the blue-light region, while the pristine h-BN has a wider indirect band gap of 4.78 eV. The hole-doped H2BN is stable at low carrier density (n) but becomes dynamically unstable at higher n. We predict that it is a phonon-mediated superconductor with a transition temperature (T-c) which can reach similar to 31 K at n of 1.5 x 10(14) holes cm(-2) near the lattice instability. The T-c could be enhanced up to similar to 82 K by applying a biaxial tensile strain at 6% along with doping at n of 3.4 x 10(14) holes cm(2) close to a new lattice instability.