Polarization switching induced by domain wall sliding in two-dimensional ferroelectric monochalcogenides

The ability to switch between distinct states of polarization comprises the defining property ferroelectrics. However, microscopic mechanism responsible for switching is not well understood and theoretical estimates based on coherent monodomain typically overestimate experimentally determined coercive fields by orders magnitude. In this work we present a detailed first principles characterization domain walls (DWs) in two-dimensional ferroelectric GeS, GeSe, SnS SnSe. particular, calculate formation energies migration barriers 180 90 DWs, then derive general expression field assuming that mediated DW migration. We apply our approach materials studied obtain good agreement with experimental fields. calculated are up two magnitude smaller than those predicted from Finally, study optical properties compounds find presence DWs leads significant red shift absorption spectrum, implying density may be means simple probes.