Spin-Ordered States in Multilayer Massless Dirac Fermion Systems

TL;DR

This paper explores spin-ordered states in multilayer massless Dirac fermion systems under magnetic fields, revealing ferromagnetic order with unique g-factors, using mean field theory applied to alpha-(BEDT-TTF)2I3.

Contribution

It introduces a theoretical analysis of spin ordering in multilayer Dirac systems considering both intra- and interlayer interactions, applying it specifically to alpha-(BEDT-TTF)2I3.

Findings

Weak interlayer coupling leads to ferromagnetic spin order.

The effective Zeeman g-factor is less than two, differing from single-layer graphene.

The study provides insights into magnetic properties of multilayer Dirac systems.

Abstract

We investigate the spin-ordered states in multilayer massless Dirac fermion systems under magnetic fields, in which the intralayer interaction is ferromagnetic owing to the exchange interaction, while the interlayer interaction is antiferromagnetic arising from the interlayer hopping and the on-site Coulomb repulsion. The possible spin-ordered states are examined within the mean field theory, and we apply it to alpha-(BEDT-TTF)2I3, which is a multilayer massless Dirac fermion system under pressure. In the weak interlayer coupling regime the system exhibits a ferromagnetically spin-ordered state with the effective Zeeman g-factor less than two contrasting to that observed in the single-layer graphene.