中国物理B ›› 2021, Vol. 30 ›› Issue (7): 77302-077302.doi: 10.1088/1674-1056/ac078c

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Thermodynamic criterion for searching high mobility two-dimensional electron gas at KTaO3 interface

Wen-Xiao Shi(时文潇)1,2, Hui Zhang(张慧)1,2, Shao-Jin Qi(齐少锦)1,2, Jin-E Zhang(张金娥)1,2, Hai-Lin Huang(黄海林)1,2, Bao-Gen Shen(沈保根)1, Yuan-Sha Chen(陈沅沙)1,3,†, and Ji-Rong Sun(孙继荣)1,4,5,‡   

  1. 1 Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Fujian Innovation Academy, Chinese Academy of Sciences, Fuzhou 350108, China;
    4 Songshan Lake Materials Laboratory, Dongguan 523808, China;
    5 Spintronics Institute, University of Jinan, Jinan 250022, China
  • 收稿日期:2021-02-01 修回日期:2021-03-22 接受日期:2021-06-03 出版日期:2021-06-22 发布日期:2021-06-24
  • 通讯作者: Yuan-Sha Chen, Ji-Rong Sun E-mail:yschen@iphy.ac.cn;jrsun@iphy.ac.cn
  • 基金资助:
    Project supported by the National Key R&D Program of China (Grant Nos. 2016YFA0300701, 2017YFA0206304, and 2018YFA0305704), the National Natural Science Foundation of China (Grant Nos. 11934016, 111921004, 51972335, and 11674378), and the Key Program of the Chinese Academy of Sciences (Grant Nos. XDB33030200 and QYZDY-SSW-SLH020).

Thermodynamic criterion for searching high mobility two-dimensional electron gas at KTaO3 interface

Wen-Xiao Shi(时文潇)1,2, Hui Zhang(张慧)1,2, Shao-Jin Qi(齐少锦)1,2, Jin-E Zhang(张金娥)1,2, Hai-Lin Huang(黄海林)1,2, Bao-Gen Shen(沈保根)1, Yuan-Sha Chen(陈沅沙)1,3,†, and Ji-Rong Sun(孙继荣)1,4,5,‡   

  1. 1 Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Fujian Innovation Academy, Chinese Academy of Sciences, Fuzhou 350108, China;
    4 Songshan Lake Materials Laboratory, Dongguan 523808, China;
    5 Spintronics Institute, University of Jinan, Jinan 250022, China
  • Received:2021-02-01 Revised:2021-03-22 Accepted:2021-06-03 Online:2021-06-22 Published:2021-06-24
  • Contact: Yuan-Sha Chen, Ji-Rong Sun E-mail:yschen@iphy.ac.cn;jrsun@iphy.ac.cn
  • Supported by:
    Project supported by the National Key R&D Program of China (Grant Nos. 2016YFA0300701, 2017YFA0206304, and 2018YFA0305704), the National Natural Science Foundation of China (Grant Nos. 11934016, 111921004, 51972335, and 11674378), and the Key Program of the Chinese Academy of Sciences (Grant Nos. XDB33030200 and QYZDY-SSW-SLH020).

摘要: Two-dimensional electron gases (2DEGs) formed at the interface between two oxide insulators present a promising platform for the exploration of emergent phenomena. While most of the previous works focused on SrTiO$_{3}$-based 2DEGs, here we took the amorphous-ABO$_{3}$/KTaO$_{3}$ system as the research object to study the relationship between the interface conductivity and the redox property of B-site metal in the amorphous film. The criterion of oxide-oxide interface redox reactions for the B-site metals, Zr, Al, Ti, Ta, and Nb in conductive interfaces was revealed: the formation heat of metal oxide, ${\Delta H}_{\rm f}^{\rm o}$, is lower than $-350 $ kJ/(mol O) and the work function of the metal $\varPhi $ is in the range of 3.75 eV$ <\varPhi <4.4$ eV. Furthermore, we found that the smaller absolute value of ${\Delta H}_{\rm f}^{\rm o}$ and the larger value of $\varPhi $ of the B-site metal would result in higher mobility of the two-dimensional electron gas that formed at the corresponding amorphous-ABO$_{3}$/KTaO$_{3}$ interface. This finding paves the way for the design of high-mobility all-oxide electronic devices.

关键词: two-dimensional electron gas, oxygen vacancies, thermodynamic criterion, Hall mobility

Abstract: Two-dimensional electron gases (2DEGs) formed at the interface between two oxide insulators present a promising platform for the exploration of emergent phenomena. While most of the previous works focused on SrTiO$_{3}$-based 2DEGs, here we took the amorphous-ABO$_{3}$/KTaO$_{3}$ system as the research object to study the relationship between the interface conductivity and the redox property of B-site metal in the amorphous film. The criterion of oxide-oxide interface redox reactions for the B-site metals, Zr, Al, Ti, Ta, and Nb in conductive interfaces was revealed: the formation heat of metal oxide, ${\Delta H}_{\rm f}^{\rm o}$, is lower than $-350 $ kJ/(mol O) and the work function of the metal $\varPhi $ is in the range of 3.75 eV$ <\varPhi <4.4$ eV. Furthermore, we found that the smaller absolute value of ${\Delta H}_{\rm f}^{\rm o}$ and the larger value of $\varPhi $ of the B-site metal would result in higher mobility of the two-dimensional electron gas that formed at the corresponding amorphous-ABO$_{3}$/KTaO$_{3}$ interface. This finding paves the way for the design of high-mobility all-oxide electronic devices.

Key words: two-dimensional electron gas, oxygen vacancies, thermodynamic criterion, Hall mobility

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

  • 73.20.-r
68.35.Md (Surface thermodynamics, surface energies) 73.40.-c (Electronic transport in interface structures)