Design principles for selecting interfaces between Rashba compound and a ferroelectric film that would reverse spin texture

The reversal of Rashba (R) dipoles and thus the ensuing spin texture is expected to be achieved at interfaces between a ferroelectric (FE) compound and a R compound upon the switching of the FE polarization. However, not all the FE/R pairs can accomplish such reversal. Using DFT calculations, a set of epitaxial interfaces between a PbTiO₃ FE film and a variety of top layer materials acting as permanent or induced R films have been investigated. We find the minimal design principles leading to R spin texture reversal through ferroelectric switching. These conditions include: (i) The two FE polarizations must be retained after the interface atomic relaxation; (ii) The direction of electron transfer between the FE and R must be reversed when the FE polarization is switched; (iii) the R dipole must be reversed at least in one of its vector component directions when the FE polarization is switched; (iv)The R bands must have orbital components parallel to the direction of the reversed R dipole component. We give examples where these conditions are or are not satisfied, examining the consequences on texture, thus enabling better understanding of the microscopic features that control the desired R spin texture reversal.