Ferroelectricity in wurtzite structure simple chalcogenide

Abstract

The possibility of the new class ferroelectric materials of wurtzite structure simple chalcogenide was discussed using modern first-principles calculation technique. Ferroelectricity in the wurtzite structure (P63mc) can be understood by structure distortion from centrosymmetric P63/mmc by relative displacement of cation against anion along c-axis. Calculated potential surface of these compounds shows typical double well between two polar variants. The potential barriers for the ferroelectric polarization switching were estimated to be 0.25 eV/f.u. for ZnO. It is slightly higher energy to the common perovskite ferroelectric compound PbTiO3. Epitaxial tensile strain on the ab-plane (0001) is effective to lower the potential barrier. The potential barrier decreased from 0.25 to 0.15 eV/f.u. by 5% ab-plane expansion in wurtzite structure ZnO. Epitaxial ZnO thin film with donor type defect reduction should be a possible candidate to confirm this ferroelectricity in wurtzite structure simple chalcogenide.