Dislocations and the enhancement of superconductivity in odd-parity superconductor Sr$_2$RuO$_4$

TL;DR

This study reveals that lattice dislocations can enhance superconductivity in Sr$_2$RuO$_4$, an odd-parity superconductor, challenging previous assumptions about disorder effects and highlighting the role of order parameter symmetry.

Contribution

It demonstrates the enhancement of superconductivity near dislocations in Sr$_2$RuO$_4$ and links this to the two-component nature of its order parameter through phenomenological theory.

Findings

Superconductivity is enhanced near lattice dislocations.

No increase in vortex pinning strength was observed.

Enhancement is related to symmetry reduction effects.

Abstract

We report observation of the enhancement of superconductivity near lattice dislocations and the absence of the strengthening of vortex pinning in odd-parity superconductor Sr$_2$RuO$_4$, both surprising results in direct contrast to the well known sensitivity of superconductivity in Sr$_2$RuO$_4$ to disorder. The enhanced superconductivity appears to be related fundamentally to the two-component nature of the superconducting order parameter, as revealed in our phenomenological theory taking into account the effect of symmetry reduction near a dislocation.