Depolarization of few-layer III–V and II–VI materials through symmetric rumpling. Issue 20 (17th May 2022)

• Record Type: Journal Article
• Authors: Sun, An-An; Gao, Shang-Peng
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 20(2022)
• Page Start: 12621
• Page End: 12630
• Publication Date: 2022-05-17
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp01715f
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A stabilization mechanism is unraveled for III–V and II–VI films to remove the dipoles by adopting a symmetrically rumpled configuration. Abstract : It is generally believed that few-layer films of wurtzite materials remove the destabilizing dipole by converting to a flat hexagonal structure. However, using first-principles calculations, we demonstrate that contrary to the existing consensus these few-layer hexagonal films exhibit a small symmetric rumpling and are not perfectly flat. We then perform a systematic study of the rumpling behavior of a range of few-layer III–V and II–VI films. The symmetric rumpled configuration enables such films to cancel out the dipole and thereby to avoid the polar instability. This stabilization mechanism is quite distinct from those known for bulk and few-layer polar materials. Compared to the perfectly flat films, the rumpled films exhibit lower electrostatic potential energy, lower total energy, higher bonding strength, and thus greater stability and larger band gaps. We also discuss the relationship between rumpling behavior, interlayer interactions, and ionicity through electrostatic analysis.