Giant magneto-optical response in non-magnetic semiconductor BiTeI driven by bulk Rashba spin splitting

TL;DR

This study reveals that the non-magnetic semiconductor BiTeI exhibits a giant magneto-optical response driven by bulk Rashba spin splitting, with potential for enhanced effects near the Dirac point, based on experimental and theoretical analysis.

Contribution

The paper demonstrates that giant MO activity in BiTeI arises from Rashba-split conduction bands, providing new insights into non-magnetic MO effects and predicting enhanced responses near the Dirac point.

Findings

Giant MO response observed in BiTeI under moderate magnetic fields.

Enhanced MO activity linked to intraband transitions between Rashba-split bands.

Predicted even stronger effects near the conduction band crossing (Dirac point).

Abstract

We study the magneto-optical (MO) response of polar semiconductor BiTeI with giant bulk Rashba spin splitting at various carrier densities. Despite being non-magnetic, the material is found to yield a huge MO activity in the infrared region under moderate magnetic fields (<3 T). By comparison with first-principles calculations, we show that such an enhanced MO response is mainly due to the intraband transitions between the Rashba-split bulk conduction bands in BiTeI, which give rise to distinct novel features and systematic doping dependence of the MO spectra. We further predict an even more pronounced enhancement in the low-energy MO response and dc Hall effect near the crossing (Dirac) point of the conduction bands.