Correlation between superconductivity, band filling, and electron confinement at the LaAlO3/SrTiO3 interface

A. E.M. Smink (Corresponding Author), M. P. Stehno, J. C. De Boer, A. Brinkman, W. G. Van Der Wiel, H. Hilgenkamp

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Abstract

By combined top- and backgating, we explore the correlation of superconductivity with band filling and electron confinement at the LaAlO3/SrTiO3 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 Tc to the corresponding evolution of the band filling with gate voltage. For several backgate voltages, we observe maximum Tc 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 dxy subband. These results establish a major role for confinement-induced subbands in the phase diagram of SrTiO3 surface states, and establish gating as a means to control the relative energy of these states.

Original languageEnglish
Article number245113
JournalPhysical review B: Covering condensed matter and materials physics
Volume97
Issue number24
DOIs
Publication statusPublished - 8 Jun 2018

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Superconductivity
superconductivity
Electrons
Electric potential
electric potential
electrons
confining
high voltages
critical temperature
Surface states
tuning
phase diagrams
Phase diagrams
Tuning
strontium titanium oxide
energy
Temperature

Cite this

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abstract = "By combined top- and backgating, we explore the correlation of superconductivity with band filling and electron confinement at the LaAlO3/SrTiO3 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 Tc to the corresponding evolution of the band filling with gate voltage. For several backgate voltages, we observe maximum Tc to consistently coincide with a kink in tuning the band filling for high topgate voltage. Self-consistent Schr{\"o}dinger-Poisson calculations relate this kink to a Lifshitz transition of the second dxy subband. These results establish a major role for confinement-induced subbands in the phase diagram of SrTiO3 surface states, and establish gating as a means to control the relative energy of these states.",
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T1 - Correlation between superconductivity, band filling, and electron confinement at the LaAlO3/SrTiO3 interface

AU - Smink, A. E.M.

AU - Stehno, M. P.

AU - De Boer, J. C.

AU - Brinkman, A.

AU - Van Der Wiel, W. G.

AU - Hilgenkamp, H.

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AB - By combined top- and backgating, we explore the correlation of superconductivity with band filling and electron confinement at the LaAlO3/SrTiO3 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 Tc to the corresponding evolution of the band filling with gate voltage. For several backgate voltages, we observe maximum Tc 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 dxy subband. These results establish a major role for confinement-induced subbands in the phase diagram of SrTiO3 surface states, and establish gating as a means to control the relative energy of these states.

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