title: Limit of the electrostatic doping in two-dimensional electron gases of LaXO₃(X = Al, Ti)/SrTiO₃.
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.
authors.affiliation: LPEM- UMR8213/CNRS - ESPCI ParisTech - UPMC, 10 rue Vauquelin - 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Biscaras
authors.affiliation: LPEM- UMR8213/CNRS - ESPCI ParisTech - UPMC, 10 rue Vauquelin - 75005 Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Hurand
authors.affiliation: LPEM- UMR8213/CNRS - ESPCI ParisTech - UPMC, 10 rue Vauquelin - 75005 Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Feuillet-Palma
authors.affiliation: Condensed Matter - Low Dimensional Systems Laboratory, Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India.
authors.forename: A
authors.initials: A
authors.lastname: Rastogi
authors.affiliation: 1] Condensed Matter - Low Dimensional Systems Laboratory, Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016, India [2] National Physical Laboratory, New Delhi - 110012, India and.
authors.forename: R C
authors.initials: RC
authors.lastname: Budhani
authors.affiliation: Unité Mixte de Physique CNRS-Thales, 1 Av. A. Fresnel, 91767 Palaiseau, France.
authors.forename: N
authors.initials: N
authors.lastname: Reyren
authors.affiliation: Unité Mixte de Physique CNRS-Thales, 1 Av. A. Fresnel, 91767 Palaiseau, France.
authors.forename: E
authors.initials: E
authors.lastname: Lesne
authors.affiliation: LPEM- UMR8213/CNRS - ESPCI ParisTech - UPMC, 10 rue Vauquelin - 75005 Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Lesueur
authors.affiliation: LPEM- UMR8213/CNRS - ESPCI ParisTech - UPMC, 10 rue Vauquelin - 75005 Paris, France.
authors.forename: N
authors.initials: N
authors.lastname: Bergeal