Mechanisms of enhanced orbital dia- and paramagnetism: Application to the Rashba semiconductor BiTeI
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 EF is near the crossing point of the conduction bands, while the susceptibility turns to be paramagnetic when EF 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 EF due to band (anti)crossings. Based on these observations, we propose two mechanisms for an enhanced paramagnetic orbital susceptibility.