Site-selective NMR for odd-frequency Cooper pairs around vortex in chiral p-wave superconductors

TL;DR

This paper proposes a site-selective NMR method to distinguish chiral p-wave superconducting states by analyzing local relaxation rates, revealing differences based on chirality and vortex core phenomena.

Contribution

It introduces a theoretical approach to identify pairing symmetry in chiral p-wave superconductors using site-selective NMR and calculates local relaxation rates considering magnetic field effects.

Findings

1/T_1 varies between chiral states depending on chirality and vorticity alignment.

Anomalous suppression of 1/T_1 occurs around vortex cores in the p_- wave due to odd-frequency pairing.

Differences in NMR line shape can indicate the presence of Majorana states.

Abstract

In order to identify the pairing symmetry with chirality, we study site-selective NMR in chiral p-wave superconductors. We calculate local nuclear relaxation rate 1/T_1 in the vortex lattice state by Eilenberger theory, including the applied magnetic field dependence. We find that 1/T_1 in the NMR resonance line shape is different between two chiral states p_{pm}(=p_x{pm}ip_y), depending on whether the chirality is parallel or anti-parallel to the vorticity. Anomalous suppression of 1/T_1 occurs around the vortex core in the chiral p_- wave due to the negative coherence term coming from the odd-frequency s-wave Cooper pair induced around the vortex with Majorana state.