Theoretical prediction of superconductivity in monolayer B3N

Using first-principles calculations, we predict the two-dimensional (2D) monolayer boron-nitrogen compound ${\mathrm{B}}_{3}\mathrm{N}$, which shows a honeycomb lattice similar to graphene. Its stability is proved by phonon spectra and ab initio molecular dynamics simulations. Since pristine ${\mathrm{B}}_{3}\mathrm{N}$ is a metal by band structure calculation, we investigate the electron-phonon coupling and possible phonon-mediated superconductivity. Based on the Eliashberg equation, the calculated electron-phonon coupling strength is about 0.66, and the superconducting transition temperature ${T}_{c}$ is 14.1 K, which is comparable to that of borophene. Furthermore, when 0.04 electron/cell doping and 10% biaxial tensile strain are applied, ${T}_{c}$ can be increased to 17.4 K. Thus, the predicted ${\mathrm{B}}_{3}\mathrm{N}$ provides a platform for 2D superconductivity.