1. Limit of the electrostatic doping in two-dimensional electron gases of LaXO3(X = Al, Ti)/SrTiO3
- Author
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R. C. Budhani, Nicolas Bergeal, Cheryl Feuillet-Palma, J. Biscaras, Nicolas Reyren, Edouard Lesne, S. Hurand, A. Rastogi, Jerome Lesueur, Laboratoire de Physique et d'Etude des Matériaux (UMR 8213) (LPEM), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Kanpur], Indian Institute of Technology Kanpur (IIT Kanpur), CSIR National Physical Laboratory [New Delhi], Council of Scientific and Industrial Research [India] (CSIR), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), and Centre National de la Recherche Scientifique (CNRS)-THALES
- Subjects
Superconductivity ,Multidisciplinary ,Materials science ,Condensed matter physics ,Doping ,Heterojunction ,Fermi energy ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,[SPI.TRON]Engineering Sciences [physics]/Electronics ,Condensed Matter::Materials Science ,Electrical resistivity and conductivity ,Condensed Matter::Superconductivity ,Condensed Matter::Strongly Correlated Electrons ,Fermi gas ,Quantum well - Abstract
In LaTiO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures, the bending of the SrTiO3 conduction band at the interface forms a quantum well that contains a superconducting two-dimensional electron gas (2-DEG). Its carrier density and electronic properties, such as superconductivity and Rashba spin-orbit coupling can be controlled by electrostatic gating. In this article we show that the Fermi energy lies intrinsically near the top of the quantum well. Beyond a filling threshold, electrons added by electrostatic gating escape from the well, hence limiting the possibility to reach a highly-doped regime. This leads to an irreversible doping regime where all the electronic properties of the 2-DEG, such as its resistivity and its superconducting transition temperature, saturate. The escape mechanism can be described by the simple analytical model we propose.
- Published
- 2014
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