By means of density functional theory calculations, we predict that several two dimensional AB binary monolayers, where A and B atoms belong to group IV or III-V, are ferroelectric. Dipoles arise from the buckled structure, where the A and B ions are located on the sites of a bipartite corrugated honeycomb lattice with trigonal symmetry. We discuss the emerging valley-dependent properties and the coupling of spin and valley physics, which arise from the loss of inversion symmetry, and explore the interplay between ferroelectricity and Rashba spin-spitting phenomena. We show that valley-related properties originate mainly from the binary nature of AB monolayers, while the Rashba spin-texture developing around valleys is fully controllable and switchable by reversing the ferroelectric polarization.
@article{arxiv.1412.8675,
title = {Emergence of ferroelectricity and spin-valley properties in two-dimensional honeycomb binary compounds},
author = {Domenico Di Sante and Alessandro Stroppa and Paolo Barone and Myung-Hwan Whangbo and Silvia Picozzi},
journal= {arXiv preprint arXiv:1412.8675},
year = {2015}
}