Impurities and orbital dependent superconductivity in Sr_2RuO_4

TL;DR

This paper investigates how impurities affect the orbital-dependent superconductivity in Sr_2RuO_4, revealing that even low impurity levels significantly impact its low-temperature properties due to its unique odd-parity pairing state.

Contribution

It provides a theoretical analysis of impurity effects on orbital-dependent superconductivity in Sr_2RuO_4 within the Born approximation, highlighting its unconventional sensitivity.

Findings

Impurities strongly influence low-temperature behavior.

Orbital dependence affects impurity scattering impact.

Unique superconducting state differs from typical nodeless p-wave expectations.

Abstract

There now exists a wealth of experimental evidence that Sr_2RuO_4 is an odd-parity superconductor. Experiments further indicate that among the bands stemming from the Ru {xy,xz,yz} orbitals, the portion of the Fermi surface arising from the xy orbitals exhibits a much larger gap than the portions of the Fermi surface arising from the {xz,yz} orbitals. In this paper the role of impurities on such an orbital dependent superconducting state is examined within the Born approximation. In contrast to expected results for a nodeless p-wave superconductor the unique nature of the superconducting state in Sr_2RuO_4 implies that a low concentration of impurities strongly influences the low temperature behavior.