Electron-phonon interaction in Ca2N monolayer: intrinsic mobility of electrene

Electron-phonon(e-ph) interaction in Ca2N monolayer, the first electrene material with two-dimensional(2D) electron gas floating in free space, is expected to be very weak and such a character can be used to design weak-scattering transport channels. Therefore, it is highly desirable to quantitatively evaluate the carrier mobility of electrene. In this study, e-ph interaction in Ca2N monolayer is investigated using a precise Wannier interpolation-based first principles technique. The calculated e-ph coupling matrix elements of Ca2N monolayer are indeed small compared to other 2D materials such as graphene, which leads to an intrinsic mobility of 189 cm2V-1s-1, much higher than those of conventional metals. Other factors affecting mobility are discussed in a comparison with graphene. It is predicted that, based on a momentum mismatch mechanism, mobility of Ca2N monolayer can be increased further to above 3000 cm2V-1s-1 via hole doping. Our results confirm that Ca2N electrene is a promising electronic material.