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 Rashba spin-split conduction bands at the time-reversal symmetry point $A$. On the other hand, when $E_F$ is below this band crossing, the susceptibility turns to be paramagnetic. 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 the enhanced paramagnetic orbital susceptibility.

• Received 8 November 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.247208