Emergence of ferroelectricity and spin-valley properties in two-dimensional honeycomb binary compounds

First-principles calculations presented in this Rapid Communication suggest that a number of A00exB binary honeycomb monolayers should be ferroelectric. Dipoles arise from the buckled structure, and the polarization reversal occurs via switching the structural buckling which can be triggered by an external electric field. The authors address the emerging valley-dependent properties arising from the ferroelectric bistability and explore the intimate link between ferroelectricity, spin-valley physics, and Rashba spin-splitting phenomena.