# Possibility of chiral $d$-wave state in the hexagonal pnictide superconductor SrPtAs

## TL;DR

This paper explores the potential for a chiral d-wave superconducting state in SrPtAs, showing it can be consistent with experimental data traditionally interpreted as supporting s-wave pairing.

## Contribution

It demonstrates that recent experimental results do not exclude the chiral d-wave state, emphasizing the importance of multiband structure in understanding pairing symmetry.

## Key findings

- Chiral d-wave state is compatible with NMR and superfluid density data.
- Multiband effects are crucial in reconciling experimental observations.
- Chiral d-wave pairing remains a viable candidate in SrPtAs.

## Abstract

We discuss the type of pairing in the hexagonal pnictide superconductor SrPtAs, taking into account its multiband structure. The topological chiral $d$-wave state with time-reversal-symmetry breaking has been anticipated from the spontaneous magnetization observed by the muon-spin-relaxation experiment. We point out in this paper that the recent experimental reports on the nuclear-spin-lattice relaxation rate $T_1^{-1}$ and superfluid density $n_s(T)$, which seemingly support the conventional $s$-wave pairing, are also consistent with the chiral $d$-wave state. The compatibility of the gap and multiband structures is crucial in this argument.