Diluted magnetic Dirac-Weyl materials: Susceptibility and ferromagnetism in three-dimensional chiral gapless semimetals

TL;DR

This paper theoretically explores the magnetic susceptibility and ferromagnetic ordering in three-dimensional chiral gapless semimetals with various band dispersions, revealing that these materials can exhibit ferromagnetism mediated by magnetic impurities, with transition temperatures depending on band structure.

Contribution

It introduces a theoretical framework for understanding magnetic properties in 3D chiral semimetals with arbitrary dispersion, highlighting the role of band structure in ferromagnetic transition temperatures.

Findings

Ferromagnetic ordering occurs in all studied chiral semimetals with magnetic impurities.

The Curie temperature increases with the dispersion parameter N.

Calculated transition temperatures are experimentally accessible.

Abstract

We theoretically investigate the temperature-dependent static susceptibility and long-range magnetic coupling of three-dimensional (3D) chiral gapless electron-hole systems (semimetals) with arbitrary band dispersion [i.e., $\varepsilon(k) \sim k^N$, where $k$ is the wave vector and $N$ is a positive integer]. We study the magnetic properties of these systems in the presence of dilute random magnetic impurities. Assuming carrier-mediated Ruderman-Kittel-Kasuya-Yosida indirect exchange interaction, we find that the magnetic ordering of intrinsic 3D chiral semimetals in the presence of dilute magnetic impurities is ferromagnetic for all values of $N$. Using finite-temperature self-consistent field approximation, we calculate the ferromagnetic transition temperature ($T_{\rm c}$). We find that $T_{\rm c}$ increases with increasing $N$ due to the enhanced density of states, and the calculated $T_{\rm c}$ is experimentally accessible assuming reasonable coupling between the magnetic impurities and itinerant carriers.