Localized magnetic moments in a Dirac semimetal as a spin model with long--range interactions

TL;DR

This paper explores the thermodynamics of localized magnetic moments in Dirac semimetals, linking electron-mediated interactions to long-range spin models and suggesting a new disordered fixed point based on high-temperature expansion results.

Contribution

It introduces a connection between magnetic impurity thermodynamics in Dirac semimetals and long-range spin models, proposing a new disordered fixed point.

Findings

High-temperature expansion indicates a new disordered fixed point.

Effective ferromagnetic exchange mediated by relativistic electrons.

Connection between impurity thermodynamics and long-range interactions.

Abstract

We connect between the problem of thermodynamics of localized magnetic moments in a Dirac semimetal, the interaction with relativistic electrons leading to the effective ferromagnetic exchange between the moments, and the existing theories dealing with long--range exchange interaction. We point out that the results of high--temperature expansion for the free energy of a dilute ensemble of magnetic impurities in the semimetal performed by V. Cheianov et al. (Phys. Rev. B {\bf 86}, 054424 (2012)) give an indication to the existence of a new disordered fixed point in such model.