Signatures of interfacial topological chiral modes via RKKY exchange interaction in Dirac and Weyl systems

TL;DR

This paper theoretically explores how interfacial chiral bound states in domain walls of Dirac and Weyl systems influence RKKY exchange interactions between magnetic impurities, revealing signatures of topological chiral modes.

Contribution

It introduces a model for interfacial bound states in domain walls and demonstrates their signatures in RKKY interactions, highlighting topological chiral modes in Dirac and Weyl materials.

Findings

Interfacial chiral bound states produce distinct signatures in RKKY exchange.

RKKY interactions are robust against quantum well deformations.

Zero-energy modes with opposite chiralities are key to the observed effects.

Abstract

We theoretically investigate the features of Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interaction between two magnetic impurities, mediated by the interfacial bound states inside a domain wall (DW). The latter separates the two regions with oppositely signed inversion symmetry broken terms in graphene and Weyl semimetal. The DW is modelled by a smooth quantum well which hosts a number of discrete bound states including a pair of gapless, metallic zero-energy modes with opposite chiralities. We find clear signatures of these interfacial chiral bound states in spin response (RKKY exchange interaction) which is robust to the deformation of the quantum well.