Ferromagnetism in layered metallic Fe1/4TaS2 in the presence of conventional and Dirac carriers

TL;DR

This study investigates the microscopic origin of ferromagnetism in Fe0.25TaS2, revealing the coexistence of conventional and Dirac carriers and deriving an effective Hamiltonian that explains its high Curie temperature and magnetic anisotropy.

Contribution

It introduces a detailed microscopic model for Fe0.25TaS2 incorporating both carrier types and explains its magnetic properties using a novel RKKY-type Hamiltonian.

Findings

Coexistence of conventional and Dirac carriers in Fe0.25TaS2

Derivation of an effective RKKY-type Hamiltonian including multiple spin interactions

High Curie temperature and large magnetic anisotropy explained by the model

Abstract

In this paper we present the microscopic origin of the ferromagnetism of Fe0.25TaS2 and its finite-temperature magnetic properties. We first obtain the band structures of Fe0.25TaS2 by the first-principles calculations and find that both conventional and Dirac carriers coexist in metallic Fe0.25TaS2. Accordingly, considering the spin-orbit coupling of Fe 3d ion, we derive an effective RKKY-type Hamiltonian between Fe spins in the presence of both the conventional parabolic-dispersion and the Dirac linear-dispersion carriers, which contains a Heisenberg-like, an Ising-like and an XY-like term. In addition, we obtain the ferromagnetic Curie temperature Tc by using the cluster self-consistent field method. Our results could address not only the high ferromagnetic Curie temperature, but also the large magnetic anisotropy in FexTaS2.