Stabilizing forces acting on ZnO polar surfaces: STM, LEED, and DFT

H. Xu*, L. Dong, X. Q. Shi, M. A. VAN HOVE, W. K. Ho, N. Lin, H. S. Wu, S. Y. Tong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

Abstract

New understanding has been reached on competing forces acting to stabilize the polar surfaces of intrinsic ZnO. To compensate an accumulating dipole moment normal to ionic planes, the Madelung electrostatic force and the bonding ability of undercoordinated Zn ions compete to deplete more Zn atoms from the (0001) face and more O atoms from the (0001̄) face. In this competition, the former mechanism wins because it provides very low energy binding sites for O ions at face-centered-cubic registries on both surfaces. On the Zn-face, a distorted tetrahedral structure is formed, while on the O-face, a vertical Y structure is formed. In both structures, O ions form the topmost atomic plane. The reconstructed polar surfaces containing these novel structures have cleavage energy of 2.36 J/m2, comparable to that of nonpolar surfaces and in agreement with experimental observation. An earlier structure found on the Zn-face annealed at below 1000 K is stabilized mainly by the Madelung electrostatic force and is a metastable structure of that surface.

Original languageEnglish
Article number235403
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number23
DOIs
Publication statusPublished - 5 Jun 2014

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Stabilizing forces acting on ZnO polar surfaces: STM, LEED, and DFT'. Together they form a unique fingerprint.

Cite this