Mechanisms of enhanced orbital dia- and paramagnetism: Application to the Rashba semiconductor BiTeI

TL;DR

This paper investigates the orbital magnetism in the Rashba semiconductor BiTeI, revealing temperature-dependent diamagnetism and paramagnetism linked to Fermi energy positioning, supported by theoretical calculations.

Contribution

It introduces two mechanisms explaining enhanced paramagnetic orbital susceptibility in BiTeI, combining experimental observations with first-principles calculations.

Findings

Large temperature-dependent diamagnetic susceptibility near E_F crossing point

Susceptibility becomes paramagnetic when E_F is away from crossing point

First-principles calculations predict sign-changing orbital magnetic susceptibility

Abstract

We study the magnetic susceptibility of a layered semiconductor BiTeI with giant Rashba spin splitting both theoretically and experimentally to explore its orbital magnetism. Apart from the core contributions, a large temperature-dependent diamagnetic susceptibility is observed when the Fermi energy E_F is near the crossing point of the conduction bands, while the susceptibility turns to be paramagnetic when E_F is away from it. These features are consistent with first-principles calculations, which also predict an enhanced orbital magnetic susceptibility with both positive and negative signs as a function of E_F due to band (anti)crossings. Based on these observations, we propose two mechanisms for an enhanced paramagnetic orbital susceptibility.