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Stabilizing forces acting on ZnO polar surfaces: STM, LEED, and DFT
Physical Review B
  • H. Xu, Department of Physics, South University of Science and Technology of China, China
  • L. Dong, Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
  • X. Q. Shi, Department of Physics, South University of Science and Technology of China, China
  • Michel Andre Van Hove, Hong Kong Baptist University
  • W. K. Ho, Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
  • N. Lin, Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
  • H. S. Wu, Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China
  • S. Y. Tong, Department of Physics, South University of Science and Technology of China, China
Document Type
Journal Article
Disciplines
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 (0001¯) 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.
Publication Year
2014
Publisher
American Physical Society
Referreed
1
DOI
10.1103/PhysRevB.89.235403
Copyright
©2014 American Physical Society
Citation Information
H. Xu, L. Dong, X. Q. Shi, Michel Andre Van Hove, et al.. "Stabilizing forces acting on ZnO polar surfaces: STM, LEED, and DFT" Physical Review B Vol. 89 (2014) p. 235403-1 - 235403-10 ISSN: 1550235X
Available at: http://works.bepress.com/mavanhove/37/