Stacking induced nonvolatile tuning of band gap in bilayer [formula omitted

Abstract

Using density functional theory calculations, we investigate the structural and electronic properties of bilayer α phase In2Se3 corresponding to different stacking orders. We found that for bilayer the interlayer antiferroelectric tail-to-tail aligned is more stable than ferroelectric aligned. The band gap varies significantly from 0.158 eV in ferroelectric bilayer to 1.278 eV in antiferroelectric one, which is due to the spontaneous polarization field induced energy shift in the ferroelectric bilayer. Transition form antiferroelectric to ferroelectric bilayer could be realized by a proper external electric field, which corresponding to the nonvolatile tuning of band gap desired in new-generation memory devices.