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

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

Kenta K. Tanaka, Masanori Ichioka, and Seiichiro Onari

Phys. Rev. B 93, 094507 – Published 7 March 2016

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 $T_{1}^{- 1}$ in the vortex lattice state by Eilenberger theory, including the applied magnetic field dependence. We find that $T_{1}^{- 1}$ in the NMR resonance line shape is different between two chiral states $p_{\pm} (= p_{x} \pm i p_{y})$ , depending on whether the chirality is parallel or antiparallel to the vorticity. Anomalous suppression of $T_{1}^{- 1}$ 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.