Slippery Paraelectric Transition-Metal Dichalcogenide Bilayers

Abstract

Traditional ferroelectrics undergo thermally induced phase transitions whereby their structural symmetry increases. The associated higher-symmetry structure is dubbed paraelectric. Ferroelectric transition-metal dichalcogenide bilayers have been recently shown to become paraelectric, but not much has been said of the atomistic configuration of such a phase. As discovered through numerical calculations that include molecular dynamics here, their paraelectricity can only be ascribed to a time average of ferroelectric phases with opposing intrinsic polarizations, whose switching requires macroscopically large areas to slip in unison.

Keywords: Brownian motion; honeycomb lattice; sliding; two-dimensional ferroelectrics; two-dimensional paraelectrics.