$\mu$SR measurements on Sr$_2$RuO$_4$ under $\langle 110 \rangle$ uniaxial stress

TL;DR

This study investigates how uniaxial stress along the 10irection affects the superconducting transition and TRSB in Sr",

Contribution

It provides new experimental evidence on the suppression of TRSB transition temperature under uniaxial stress in Sr",

Findings

TRSB transition temperature is suppressed more rapidly than $T_c$ under stress.

Preliminary evidence suggests $T_{TRSB}$ drops below $T_c$ with stress.

Uniaxial stress influences the relationship between $T_c$ and $T_{TRSB}$.

Abstract

Muon spin rotation/relaxation ($\mu$SR) and polar Kerr effect measurements provide evidence for a time-reversal symmetry breaking (TRSB) superconducting state in Sr$_2$RuO$_4$. However, the absence of a cusp in the superconducting transition temperature ($T_{\rm c}$) vs. stress and the absence of a resolvable specific heat anomaly at TRSB transition temperature ($T_{\rm TRSB}$) under uniaxial stress challenge a hypothesis of TRSB superconductivity. Recent $\mu$SR studies under pressure and with disorder indicate that the splitting between $T_{\rm c}$ and $T_{\rm TRSB}$ occurs only when the structural tetragonal symmetry is broken. To further test such behavior, we measured $T_\text{c}$ through susceptibility measurements, and $T_\text{TRSB}$ through $\mu$SR, under uniaxial stress applied along a $\langle 110 \rangle$ lattice direction. We have obtained preliminary evidence for suppression of $T_\text{TRSB}$ below $T_\text{c}$, at a rate much higher than the suppression rate of $T_\text{c}$.