Thermal Hall conductivity of spin-triplet superconductor with time reversal symmetry breaking

Yoshiki Imai,Manfred Sigrist,Katsunori Wakabayashi

doi:10.1088/1742-6596/807/10/102006

Abstract

The thermal Hall conductivity is investigated for the superconductor Sr2RuO4 assuming a time reversal symmetry breaking order parameter. The γ band of Sr2RuO4 has its Fermi level near the van Hove points, close to the Lifshitz transition. Within a Bogoliubov-de Gennes approach we calculate the thermal Hall conductivity for pairing symmetries including two exemplary cases, the usual chiral p-wave phase and a fx2−y2-wave phase of the structure . In the chiral p-wave phase the thermal Hall conductivity consists of a universal temperature-linear term and an exponential correction due to quasiparticle activation with a full excitation gap. Due to line-nodes in the gap we find a correction which is quadratic in temperature for fx2−y2-wave state. This difference in the corrections allows to analyze the gap structure of the superconducting phase.

Highlights

The transition metal oxide Sr2RuO4 [1, 2] is often viewed as a good candidate for a topological superconductor
The thermal Hall conductivity is investigated for the superconductor Sr2RuO4 assuming a time reversal symmetry breaking order parameter
The symmetry analysis has led to the identification of the pairing channel as chiral p-wave with a gap function written in dvector notation as d = Δz(kx ± iky) with an orbital angular momentum Lz = ±1 along the z axis [5]

Summary

Introduction

The transition metal oxide Sr2RuO4 [1, 2] is often viewed as a good candidate for a topological superconductor. In the chiral p-wave phase the thermal Hall conductivity consists of a universal temperature-linear term and an exponential correction due to quasiparticle activation with a full excitation gap. Due to line-nodes in the gap we find a correction which is quadratic in temperature for fx2−y2 -wave state.

Results

Conclusion