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

• Published in: 中国物理B（英文版） Vol. 30; no. 7; pp. 80 - 84
• Main Authors: Wen-Xiao Shi, Hui Zhang, Shao-Jin Qi, Jin-E Zhang, Hai-Lin Huang, Bao-Gen Shen, Yuan-Sha Chen, Ji-Rong Sun
• Format: Journal Article
• Language: English
• Published: School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100049,China%Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China%Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China 01.07.2021; Fujian Innovation Academy,Chinese Academy of Sciences,Fuzhou 350108,China%Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China; Songshan Lake Materials Laboratory,Dongguan 523808,China; Spintronics Institute,University of Jinan,Jinan 250022,China; Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China
• Subjects: two-dimensional electron gas; thermodynamic criterion; Hall mobility; oxygen vacancies
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/ac078c

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 SrTiO3-based 2DEGs,here we took the amorphous-ABO3/KTaO3 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,A1,Ti,Ta,and Nb in conductive interfaces was revealed:the formation heat of metal oxide,△H0f,is lower than-350 kJ/(mol O) and the work function of the metal Φ is in the range of 3.75 eV＜ Φ ＜ 4.4 eV.Furthermore,we found that the smaller absolute value of △H0f and the larger value of Φ of the B-site metal would result in higher mobility of the two-dimensional electron gas that formed at the corresponding amorphous-ABO3/KTaO3 interface.This finding paves the way for the design of high-mobility all-oxide electronic devices.