Large-scale modulation in the superconducting properties of thin films due to domains in the $SrTiO_{3}$ substrate

TL;DR

This study reveals that domains in SrTiO3 substrates cause large-scale modulations in the superconducting properties of thin films like Nb, NbN, and YBCO, affecting superfluid density, critical temperature, and carrier density.

Contribution

It demonstrates that SrTiO3 domains influence superconductivity in various thin films, providing insights into local control and structure-property relationships.

Findings

Superfluid density and critical temperature modulated by SrTiO3 domains

Normal current flow is also modulated over the domain structure

Domain walls in SrTiO3 remain mobile at low temperatures

Abstract

Scanning superconducting quantum interference device measurements reveal large-scale modulations of the superfluid density and the critical temperature in superconducting Nb, NbN, and underdoped $YBa_{2}Cu_{3}O_{7-{\delta}}$ films deposited on $SrTiO_{3}$ (STO). We show that these modulations are a result of the STO domains and domain walls, forming below the 105 K structural phase transition of STO. We found that the flow of normal current, measured above the superconducting transition, is also modulated over the same domain structure, suggesting a modified carrier density. In clean STO, domain walls remain mobile down to low temperatures. Modulated superconductivity over mobile channels offers the opportunity to locally control superconducting properties and better understand the relations between superconductivity and the local structure.