Strain-engineered interaction of quantum polar and superconducting phases

TL;DR

This study demonstrates that applying strain to strontium titanate significantly enhances its superconducting critical temperature, revealing a new method to control quantum phases with potential implications for quantum information science.

Contribution

First experimental demonstration of strain-induced enhancement of superconductivity in SrTiO3 by tuning its quantum polar and superconducting phases.

Findings

Nearly 50% increase in $T_c$ with strain.

Indications of potential several hundred percent increase in $T_c$.

Insights into pseudogap-like phenomena linked to local strain.

Abstract

Much of the focus of modern condensed matter physics concerns control of quantum phases with examples that include flat band superconductivity in graphene bilayers, the interplay of magnetism and ferroelectricity, and induction of topological transitions by strain. Here we report the first observation of a reproducible and strong enhancement of the superconducting critical temperature, $T_c$, in strontium titanate (SrTiO3) obtained through careful strain engineering of interacting superconducting phase and the polar quantum phase (quantum paraelectric). Our results show a nearly 50% increase in $T_c$ with indications that the increase could become several hundred percent. We have thus discovered a means to control the interaction of two quantum phases through application of strain, which may be important for quantum information science. Further, our work elucidates the enigmatic pseudogap-like and preformed electron pairs phenomena in low dimensional strontium titanate as potentially resulting from the local strain of jammed tetragonal domains.