Hybridization and anisotropy in the exchange interaction in 3D Dirac semimetals

TL;DR

This paper investigates how anisotropy and hybridization affect the RKKY interaction in 3D Dirac semimetals, revealing significant renormalization and potential for complex spin structures.

Contribution

It provides analytical expressions for the RKKY interaction considering anisotropy and hybridization, highlighting their effects on magnetic interactions in Dirac semimetals.

Findings

Fermi velocity anisotropy strongly renormalizes interaction magnitude

Anisotropic hybridization leads to spiral spin structures

Oscillation frequency of interaction is corrected by anisotropy

Abstract

We study the Ruderman-Kittel-Kasuya-Yosida interaction in 3D Dirac semimetals. Using retarded Green's functions in real space, we obtain and analyze asymptotic expressions for the interaction, with magnetic impurities at different distances and relative angle with respect to high symmetry directions on the lattice. We show that the Fermi velocity anisotropy in these materials produces a strong renormalization of the magnitude of the interaction, as well as a correction to the frequency of oscillation in real space. Hybridization of the impurities to different conduction electron orbitals are shown to result in interesting anisotropic spin-spin interactions which can generate spiral spin structures in doped samples.