Abstract Density functional theory is used to investigate the surface structures and the energies of two possible terminated LaAlO$_{3}$ (001) surfaces with oxygen vacancies, i.e. LaO- and AlO$_{2}$-terminated surfaces. The large displacements of ions, deviated from their crystalline sites, can lead to the formation of the surface rumpling. From thermodynamics analysis, the AlO$_{2}$-terminated surface with oxygen-vacancies is less stable than the LaO-terminated one. Some states in the gap lie under the Fermi level by about --1eV in the LaO-terminated surface with oxygen vacancies. For the AlO$_{2}$-terminated oxygen-vacancy surface, some O 2p states move into the mid-gap region and become partially unoccupied. The two types of termination surfaces exhibit conduction related to oxygen vacancies. Our results can contribute to the application of LAO films to high dielectric constant materials.
Received: 08 March 2007
Revised: 04 September 2007
Accepted manuscript online:
PACS:
73.20.At
(Surface states, band structure, electron density of states)
Fund: Project supported by the National
Science Fund for distinguished
Young Scholars of China (Grant No 50425207).
Cite this article:
Tang Jin-Long(唐金龙), Zhu Jun(朱俊), Qin Wen-Feng(秦文峰),Xiong Jie(熊杰), and Li Yan-Rong(李言荣) Ab initio study of oxygen-vacancy LaAlO2(001) surface 2008 Chin. Phys. B 17 655
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