Orbital magnetic susceptibility of graphene and MoS2

TL;DR

This paper calculates the orbital magnetic susceptibility of graphene and MoS2 using tight-binding models, analyzing contributions across the Brillouin zone to understand the magnetic response based on band structure.

Contribution

It provides a detailed analysis of orbital magnetic susceptibility in graphene and MoS2, distinguishing intra- and interband processes and comparing with simplified models.

Findings

Distinct intra- and interband contributions identified

Qualitative features predicted from band structure alone

Comparison with Dirac and BHZ models enhances understanding

Abstract

We calculate the orbital magnetic susceptibility $\chi_{\mathrm{orb}}$ for an 8-band tight-binding model of gapless and gapped graphene using Green's functions. Analogously, we study $\chi_{\mathrm{orb}}$ for a $\mathrm{MoS_2}$ 12-band model. For both materials, we unravel the character of the processes involved in the magnetic response by looking at the contribution at each point of the Brillouin zone. By this, a clear distinction between intra- and interband excitations is generally possible and we are able to predict qualitative features of $\chi_{\mathrm{orb}}$ only through the knowledge of the band structure. The study is complemented by comparing the magnetic response with that of 2-band lattice Hamiltonians which reduce to the Dirac and Bernevig-Hughes-Zhang (BHZ) models in the continuum limit.