Charge and spin current rectification through functionalized boron nitride bilayers.

Abstract

Recent experiments have reported the transformation of few-layer hexagonal boron nitride (h-BN) into sp3

-bonded c-BN layers through the application of pressure. A proposed mechanism, based on calculations and experiments, is that the phenomenon is facilitated by BN surface functionalization with OH or H radicals. In the present work, we perform ab initio calculations of ballistic electron transport, between Au electrodes, across such functionalized structures. We find that the stabilization of sp3 binding at zero pressure occurs for partial H coverage (≈58%), whereas large OH coverages (>75%) are necessary. Regarding transport properties, we find that all functionalized BN bilayer films present current rectification, consistent with the experimental findings. Maximum rectification occurs for partial OH and H coverages. The films also show spin-dependent transport, where, for a window of values of applied bias, a single spin component contributes to the total current, characterizing a spin filter behavior. Our results indicate that functionalized BN bilayer films are promising materials for the development of electronic devices where both charge and spin degrees of freedom might be manipulated.