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Limit of the electrostatic doping in two-dimensional electron gases of LaXO?(X = Al, Ti)/SrTiO?.

ABSTRACT: In LaTiO?/SrTiO? and LaAlO?/SrTiO? heterostructures, the bending of the SrTiO? 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.

SUBMITTER: Biscaras J

PROVIDER: S-EPMC4209450 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Limit of the electrostatic doping in two-dimensional electron gases of LaXO₃(X = Al, Ti)/SrTiO₃.

Biscaras J J Hurand S S Feuillet-Palma C C Rastogi A A Budhani R C RC Reyren N N Lesne E E Lesueur J J Bergeal N N

Scientific reports 20141027

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 elec ...[more]

PMID: 25346028

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