中国物理B ›› 2019, Vol. 28 ›› Issue (4): 47101-047101.doi: 10.1088/1674-1056/28/4/047101

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

Prediction of high-mobility two-dimensional electron gas at KTaO3-based heterointerfaces

Fu-Ning Wang(王芙凝), Ji-Chao Li(李吉超), Yi Li(李宜), Xin-Miao Zhang(张鑫淼), Xue-Jin Wang(王学晋), Yu-Fei Chen(陈宇飞), Jian Liu(刘剑), Chun-Lei Wang(王春雷), Ming-Lei Zhao(赵明磊), Liang-Mo Mei(梅良模)   

  1. School of Physics, Shandong University, Jinan 250100, China
  • 收稿日期:2018-12-27 修回日期:2019-02-13 出版日期:2019-04-05 发布日期:2019-04-05
  • 通讯作者: Ji-Chao Li E-mail:lijichao@sdu.edu.cn
  • 基金资助:

    Project supported by the National Basic Research Program of China (Grant No. 2013CB632506) and the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, and 51202132).

Prediction of high-mobility two-dimensional electron gas at KTaO3-based heterointerfaces

Fu-Ning Wang(王芙凝), Ji-Chao Li(李吉超), Yi Li(李宜), Xin-Miao Zhang(张鑫淼), Xue-Jin Wang(王学晋), Yu-Fei Chen(陈宇飞), Jian Liu(刘剑), Chun-Lei Wang(王春雷), Ming-Lei Zhao(赵明磊), Liang-Mo Mei(梅良模)   

  1. School of Physics, Shandong University, Jinan 250100, China
  • Received:2018-12-27 Revised:2019-02-13 Online:2019-04-05 Published:2019-04-05
  • Contact: Ji-Chao Li E-mail:lijichao@sdu.edu.cn
  • Supported by:

    Project supported by the National Basic Research Program of China (Grant No. 2013CB632506) and the National Natural Science Foundation of China (Grant Nos. 11374186, 51231007, and 51202132).

摘要:

First-principles calculations are performed to explore the possibility of generating the two-dimensional electron gas (2DEG) at the interface between LaGaO3/KTaO3 and NdGaO3/KTaO3 (001) heterostructures. Two different models – i.e., the superlattice model and the thin film model–are used to conduct a comprehensive investigation of the origin of charge carriers. For the symmetric superlattice model, the LaGaO3 (or NdGaO3) film is nonpolar. The 2DEG with carrier density on the order of 1014 cm-2 originates from the Ta dxy electrons contributed by both LaGaO3 (or NdGaO3) and KTaO3. For the thin film model, large polar distortions occur in the LaGaO3 and NdGaO3 layer, which entirely screens the built-in electric field and prevents electrons from transferring to the interface. Electrons of KTaO3 are accumulated at the interface, contributing to the formation of the 2DEG. All the heterostructures exhibit conducting properties regardless of the film thickness. Compared with the Ti dxy electrons in SrTiO3-based heterostructures, the Ta dxy electrons have small effective mass and they are expected to move with higher mobility along the interface. These findings reveal the promising applications of 2DEG in novel nanoelectronic devices.

关键词: 2DEG, first-principles calculation, interface

Abstract:

First-principles calculations are performed to explore the possibility of generating the two-dimensional electron gas (2DEG) at the interface between LaGaO3/KTaO3 and NdGaO3/KTaO3 (001) heterostructures. Two different models – i.e., the superlattice model and the thin film model–are used to conduct a comprehensive investigation of the origin of charge carriers. For the symmetric superlattice model, the LaGaO3 (or NdGaO3) film is nonpolar. The 2DEG with carrier density on the order of 1014 cm-2 originates from the Ta dxy electrons contributed by both LaGaO3 (or NdGaO3) and KTaO3. For the thin film model, large polar distortions occur in the LaGaO3 and NdGaO3 layer, which entirely screens the built-in electric field and prevents electrons from transferring to the interface. Electrons of KTaO3 are accumulated at the interface, contributing to the formation of the 2DEG. All the heterostructures exhibit conducting properties regardless of the film thickness. Compared with the Ti dxy electrons in SrTiO3-based heterostructures, the Ta dxy electrons have small effective mass and they are expected to move with higher mobility along the interface. These findings reveal the promising applications of 2DEG in novel nanoelectronic devices.

Key words: 2DEG, first-principles calculation, interface

中图分类号:  (Electron gas, Fermi gas)

  • 71.10.Ca
63.20.dk (First-principles theory) 67.30.hp (Interfaces)