Electric field tuning of superconductivity in lanthanum-doped strontium titanate field-effect transistors

Feng Pan; Charles T. Rogers

doi:10.1103/PhysRevB.72.094520

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Electric field tuning of superconductivity in lanthanum-doped strontium titanate field-effect transistors

Feng Pan, Charles T. Rogers

DOI 10.1103/PhysRevB.72.094520 · Physical Review B

T1

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Abstract

We report on the electric field modulation of superconductivity in thin-film field-effect transistors based on lanthanum-doped strontium titanate channels with n-type channel carrier densities in the range of 3–7×1019cm−3, thickness in the range of 70–150 nm, and with undoped strontium titanate gate insulation. Electric field tuning of normal state sheet resistance and channel critical current are observed in both enhancement and depletion modes, consistent with an electric field induced variation of channel depletion width of roughly 7.5nm∕V. Detailed analysis of the nonlinear channel current-voltage characteristics is consistent with electric field modulation of a two-dimensional Kosterlitz-Thouless transition and shows the scaling of TKT with sheet conductance at different gate fields. Small signal modulation of critical current, sheet resistance, and TKT is found for modulation frequencies out to at least 1 kHz.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
SrTiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	unknown
SrTiO3 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	0.2	Pressure not reported	onset