›› 2014, Vol. 23 ›› Issue (8): 87302-087302.doi: 10.1088/1674-1056/23/8/087302

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Stability and electronic structure studies of LaAlO3/SrTiO3 (110) heterostructures

杜颜伶a b, 王春雷a, 李吉超a, 徐攀攀a, 张新华a, 刘剑a, 苏文斌a, 梅良模a   

  1. a School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;
    b College of Science and Technology, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
  • 收稿日期:2013-11-08 修回日期:2014-02-17 出版日期:2014-08-15 发布日期:2014-08-15
  • 基金资助:
    Project supported by the National Basis Research Program of China (Grant No. 2013CB632506), the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, and 51202132), and the Independent Innovation Foundation of Shandong University, China (Grant No. 2012TS027).

Stability and electronic structure studies of LaAlO3/SrTiO3 (110) heterostructures

Du Yan-Ling (杜颜伶)a b, Wang Chun-Lei (王春雷)a, Li Ji-Chao (李吉超)a, Xu Pan-Pan (徐攀攀)a, Zhang Xin-Hua (张新华)a, Liu Jian (刘剑)a, Su Wen-Bin (苏文斌)a, Mei Liang-Mo (梅良模)a   

  1. a School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;
    b College of Science and Technology, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
  • Received:2013-11-08 Revised:2014-02-17 Online:2014-08-15 Published:2014-08-15
  • Contact: Li Ji-Chao E-mail:lijichao@sdu.edu.cn
  • Supported by:
    Project supported by the National Basis Research Program of China (Grant No. 2013CB632506), the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, and 51202132), and the Independent Innovation Foundation of Shandong University, China (Grant No. 2012TS027).

摘要: The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAlO3/SrTiO3 (110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAlO3/SrTiO3 (110) heterostructure, the Ti-O octahedron distortions cause the Ti tm 2g orbitals to split into the two-fold degenerate dxz/dyz and nondegenerate dxy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t2g orbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaAlO3 and SrTiO3 leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAlO3/SrTiO3 (110).

关键词: two-dimensional electron gas, LaAlO3/SrTiO3 (110) interface, magnetic interface

Abstract: The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAlO3/SrTiO3 (110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAlO3/SrTiO3 (110) heterostructure, the Ti-O octahedron distortions cause the Ti tm 2g orbitals to split into the two-fold degenerate dxz/dyz and nondegenerate dxy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t2g orbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaAlO3 and SrTiO3 leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAlO3/SrTiO3 (110).

Key words: two-dimensional electron gas, LaAlO3/SrTiO3 (110) interface, magnetic interface

中图分类号:  (Electron states at surfaces and interfaces)

  • 73.20.-r
75.70.Cn (Magnetic properties of interfaces (multilayers, superlattices, heterostructures)) 68.35.Md (Surface thermodynamics, surface energies)