›› 2015, Vol. 24 ›› Issue (3): 37301-037301.doi: 10.1088/1674-1056/24/3/037301

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

Two-dimensional metallic behavior at polar MgO/BaTiO3 (110) interfaces

杜颜伶a b, 王春雷a, 李吉超a, 张新华a, 王芙凝a, 刘剑a, 祝元虎a, 尹娜a, 梅良模a   

  1. a School of Physics, Shandong University, Jinan 250100, China;
    b College of Science and Technology, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
  • 收稿日期:2014-08-22 修回日期:2014-10-05 出版日期:2015-03-05 发布日期:2015-03-05
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No. 2013CB632506), the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, 51202132, and 51102153), and the Independent Innovation Foundation of Shandong University, China (Grant No. 2012TS027).

Two-dimensional metallic behavior at polar MgO/BaTiO3 (110) interfaces

Du Yan-Ling (杜颜伶)a b, Wang Chun-Lei (王春雷)a, Li Ji-Chao (李吉超)a, Zhang Xin-Hua (张新华)a, Wang Fu-Ning (王芙凝)a, Liu Jian (刘剑)a, Zhu Yuan-Hu (祝元虎)a, Yin Na (尹娜)a, Mei Liang-Mo (梅良模)a   

  1. a School of Physics, Shandong University, Jinan 250100, China;
    b College of Science and Technology, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
  • Received:2014-08-22 Revised:2014-10-05 Online:2015-03-05 Published:2015-03-05
  • Contact: Li Ji-Chao E-mail:lijichao@sdu.edu.cn
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No. 2013CB632506), the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, 51202132, and 51102153), and the Independent Innovation Foundation of Shandong University, China (Grant No. 2012TS027).

摘要: The first-principles calculations are employed to investigate the electrical properties of polar MgO/BaTiO3 (110) interfaces. Both n-type and p-type polar interfaces show a two-dimensional metallic behavior. For the n-type polar interface, the interface Ti 3d electrons are the origin of the metallic and magnetic properties. Varying the thickness of BaTiO3 may induce an insulator-metal transition, and the critical thickness is 4 unit cells. For the p-type polar interface, holes preferentially occupy the interface O 2py state, resulting in a conducting interface. The unbalance of the spin splitting of the O 2p states in the interface MgO layer leads to a magnetic moment of about 0.25μB per O atom at the interface. These results further demonstrate that other polar interfaces, besides LaAlO3/SrTiO3, can show a two-dimensional metallic behavior. It is helpful to fully understand the role of polar discontinuity on the properties of the interface, which widens the field of polar-nonpolar interfaces.

关键词: electronic structures, MgO/BaTiO3 (110) polar interfaces, two-dimensional electron gas (2DEG), magnetism

Abstract: The first-principles calculations are employed to investigate the electrical properties of polar MgO/BaTiO3 (110) interfaces. Both n-type and p-type polar interfaces show a two-dimensional metallic behavior. For the n-type polar interface, the interface Ti 3d electrons are the origin of the metallic and magnetic properties. Varying the thickness of BaTiO3 may induce an insulator-metal transition, and the critical thickness is 4 unit cells. For the p-type polar interface, holes preferentially occupy the interface O 2py state, resulting in a conducting interface. The unbalance of the spin splitting of the O 2p states in the interface MgO layer leads to a magnetic moment of about 0.25μB per O atom at the interface. These results further demonstrate that other polar interfaces, besides LaAlO3/SrTiO3, can show a two-dimensional metallic behavior. It is helpful to fully understand the role of polar discontinuity on the properties of the interface, which widens the field of polar-nonpolar interfaces.

Key words: electronic structures, MgO/BaTiO3 (110) polar interfaces, two-dimensional electron gas (2DEG), magnetism

中图分类号:  (Surface states, band structure, electron density of states)

  • 73.20.At
75.70.Cn (Magnetic properties of interfaces (multilayers, superlattices, heterostructures)) 73.20.-r (Electron states at surfaces and interfaces) 75.70.-i (Magnetic properties of thin films, surfaces, and interfaces)