Electrostatic Modulation of the Superfluid Density in a Ultrathin La2-xSrxCuO4 Film

TL;DR

This study demonstrates that applying an electric field to an ultrathin La2-xSrxCuO4 film can significantly modulate its superfluid density, providing new insights into the relationship between superfluid density and critical temperature in cuprate superconductors.

Contribution

It provides the first direct evidence of the Uemura relation in the same sample, linking superfluid density modulation to superconducting transition temperature in underdoped cuprates.

Findings

Electric field induces large changes in superfluid density.

Direct evidence supports the Uemura relation in the same sample.

Superfluid density reduction correlates with disorder effects.

Abstract

By capacitively charging an underdoped ultrathin La2-xSrxCuO4 film with an electric field applied across a gate insulator with a high dielectric constant, relative changes of the areal superfluid density n_{s\Box}$ of unprecedented strength were observed in measurements of the film kinetic inductance. Although $n_{s\Box}$ appears to be substantially reduced by disorder, the data provide, for the first time on the same sample, direct compelling evidence for the Uemura relation $T_{c} \propto n_{s\Box}(T=0)$ in the underdoped regime of copper-oxide superconductors.