Rashba Band Splitting in Organohalide Lead Perovskites: Bulk and Surface Effects.

A Rashba/Dresselhaus band splitting has been recently measured in organohalide perovskites and invoked in various experiments as a possible cause for the reduced electron-hole recombination rates observed in this class of materials. In this Perspective, we discuss the interplay of electronic and nuclear degrees of freedom in defining such an effect in realistic methylammonium lead iodide (MAPbI3) models. We distinguish between bulk and surface effects and find that, while a spatially local (in time and space) effect may be at work in the bulk, a "static" band-splitting effect is found at surfaces due to structural distortion. The proposed surface effect is consistent with the low surface recombination reported for MAPbI3 single crystals and might contribute to the success of organohalide perovskites.