Correlation between Superconductivity, Band Filling and Electron Confinement at the LaAlO${}_3$-SrTiO${}_3$ Interface

Abstract

By combined top- and backgating, we explore the correlation of superconductivity with band filling and electron confinement at the LaAlO${}_3$-SrTiO${}_3$ interface. We find that the top- and backgate voltages have distinctly different effects on the superconducting critical temperature, implying that the confining potential well has a profound effect on superconductivity. We investigate the origin of this behavior by comparing the gate-dependence of $T_c$ to the corresponding evolution of the band filling with gate voltage. For several backgate voltages, we observe maximum $T_c$ to consistently coincide with a kink in tuning the band filling for high topgate voltage. Self-consistent Schrödinger-Poisson calculations relate this kink to a Lifshitz transition of the second $d_{xy}$ subband. These results establish a major role for confinement-induced subbands in the phase diagram of SrTiO${}_3$ surface states, and establish gating as a means to control the relative energy of these states.

17 pages, 5 figures

References in corpus (14)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Alfven Waves in the Lower Solar Atmosphere
• Theory of spin-orbit coupling at LaAlO3/SrTiO3 interfaces and SrTiO3 surfaces
• Quantization of Hall Resistance at the Metallic Interface between an Oxide Insulator and SrTiO${}_3$
• Giant negative magnetoresistance driven by spin-orbit coupling at the LAO/STO interface
• Quantum and Topological Criticalities of Lifshitz Transition in Two-Dimensional Correlated Electron Systems
• Dual-Gate Modulation of Carrier Density and Disorder in an Oxide Two-Dimensional Electron System
• Gate-tunable band structure of the LaAlO${}_3$-SrTiO${}_3$ interface
• Giant tunability of the two-dimensional electron gas at the interface of gamma-Al2O3/SrTiO3
• Large modulation of the Shubnikov-de Haas oscillations by the Rashba interaction at the LaAlO${}_3$/SrTiO${}_3$ interface
• Competition between electron pairing and phase coherence in superconducting interfaces
• Quantum interference in an interfacial superconductor
• Enhanced Superconducting Transition Temperature due to Tetragonal Domains in Two-Dimensionally Doped SrTiO${}_3$
• Theoretical models of Rashba spin splitting in asymmetric SrTiO3-based heterostructures

Cited by in corpus (8)

• Electronic phase separation: recent progress in the old problem
• New insights into the electron trapping mechanism in LaAlO_3 / SrTiO3 heterostructures
• Tuning Rashba spin-orbit coupling at LaAlO3/SrTiO3 interfaces by band filling
• Competing superconducting phases in interacting two-dimensional electron gas with strong Rashba spin-orbit coupling
• Possible Flexoelectric Origin of the Lifshitz Transition in LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Artificial quantum confinement in LAO3/STO heterostructure
• Evolution of domain structure with electron doping in ferroelectric thin films
• Understanding the onset of negative electronic compressibility in one- and two-band 2D electron gases: Application to LaAlO${}_3$/SrTiO${}_3$