Homes Scaling in Ionic Liquid Gated La$_{2}$CuO$_{4+x}$ Thin Films

TL;DR

This study employs ionic liquid gating to continuously tune the superconducting transition temperature of La$_{2}$CuO$_{4+x}$ thin films, confirming Homes scaling and providing insights into their fundamental properties in the dirty limit.

Contribution

It demonstrates a systematic doping method using ionic liquid gating and verifies Homes scaling in La$_{2}$CuO$_{4+x}$ thin films, independent of gating mechanism details.

Findings

Homes scaling $ ho_s o rac{1}{ ext{penetration depth}^2}$ is obeyed

Superconducting properties are consistent with the dirty limit

Doping via ionic liquid gating effectively tunes $T_c$

Abstract

Finding more efficient ways of exploring the doping phase diagrams of high temperature superconductors as well as probing the fundamental properties of these materials are essential ingredients for driving the discovery of new materials. We use a doping technique involving gating with ionic liquids to systematically and continuously tune the T$_{c}$ of superconducting La$_{2}$CuO$_{4+x}$ thin films. We probe both the transport properties and the penetration depth of these samples and find that Homes scaling $\lambda^{-2}\propto\sigma T_{c}$ is obeyed, consistent with these materials being in the dirty limit. This result is independent of the precise mechanism for the gating process as all of the parameters of the scaling relationship are determined by direct measurements on the films.