Directional dependence of phase transition splitting by uniaxial strain: A new test to determine strontium ruthenate superconducting states

Abstract

Since the discovery of superconductivity in strontium ruthenate, there has been a widespread effort to understand its properties on a phenomenological level. To this date, there is not enough coherent experimental evidence to conclude if the superconducting phase has broken time-reversal symmetry. In this article we propose a new test based on the fact that for a multi-component order parameter, the application of uniaxial stress could cause phase transition splitting. Our analysis shows that such splitting depends on the direction of applied stress, and such directional dependence is different for every predicted superconducting phase. In particular, splitting occurs at all directions if and only if the superconducting phase is the one with broken time-reversal symmetry.