Abstract

Non-magnetic impurities can lift the accidental degeneracy of unconventional pairing states, such as the $(d + i g)$-wave state recently proposed for Sr$_2$RuO$_4$. This type of effect would lead to a superconducting double transition upon impurity doping. In a model calculation it is shown how this behavior depends on material parameters and how it could be detected.

Highlights

  • The ideal proposal for the symmetry of the order parameter of an unconventional superconductor should have the ability to explain all its specific experimental signatures

  • Experiments using uniaxial strain did not observe the splitting of the phase transition expected for the chiral p-wave state in the measurement of specific heat [10], while muon-spin rotation results show the appearance of intrinsic magnetism indicating time-reversal symmetry breaking separate from the onset of superconductivity, consistent with chiral p-wave pairing [11]

  • The two pairing states would show a different suppression of their critical temperatures under disorder, which would cause a superconducting double transition

Read more

Summary

INTRODUCTION

The ideal proposal for the symmetry of the order parameter of an unconventional superconductor should have the ability to explain all its specific experimental signatures. An alternative even-parity phase, which had been discussed in the past, is the chiral d-wave state, dzx + idyz, whose two components are degenerate analogous to those of the chiral pwave phase [13,16,17,18] This state involves interlayer pairing and has a symmetry-imposed horizontal line node at kz = 0, which would fit well with the interpretation of the magnetic field angle dependence of the specific heat by Kittaka et al [19]. Rather we would like to demonstrate how disorder affects the proposed (d + ig)-wave state and what generally expected properties could be For this purpose, we formulated a single-band model and apply the self-consistent T -matrix approximation in order to take the effect of impurity scattering on the superconducting phase into account. We examine the behavior of the two pairing channels, in particular, the splitting of their transition temperatures

Tight-binding model
Disorder-T -matrix approximation
Detecting the double transition
Findings
CONCLUSION

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.