Vortex Core Excitations in Superconductors with Frustrated Antiferromagnetism

TL;DR

This paper investigates vortex core excitations in superconductors with frustrated antiferromagnetism, revealing a chiral d+id'-wave pairing state and low-lying quasiparticle bound states, contrasting with copper oxide superconductors.

Contribution

It introduces an effective model showing a chiral d+id'-wave pairing state in frustrated antiferromagnetic superconductors and analyzes vortex core electronic structure.

Findings

No local antiferromagnetism in vortex cores.

Presence of low-lying quasiparticle bound states.

Chiral d+id'-wave pairing state prevails.

Abstract

Motivated by recent discovery of cobalt oxide and organic superconductors, we apply an effective model with strong antiferromagnetic and superconducting pairing interaction to a related lattice structure. It is found that the antiferromagnetism is highly frustrated and a broken-time-reversal-symmetry chiral $d+id^{\prime}$-wave pairing state prevails. In the mixed state, we have solved the local electronic structure near the vortex core and found no local induction of antiferromagnetism. This result is in striking contrast to the case of copper oxide superconductors. The calculated local density of states indicates the existence of low-lying quasiparticle bound states inside the vortex core, due to a fully gapped chiral pairing state. The prediction can be directly tested by scanning tunneling microscopy.