Spin splitting in 2D monochalcogenide semiconductors

• DOI: 10.1038/srep17044
• Publication Date: 2015-11-24T10:29:38Z
• Authors: Dat T. Do; Subhendra D. Mahanti; Chih Wei Lai
• Keywords: Point reflection; Brillouin zone; Rashba effect; Monoclinic crystal system

We report ab initio calculations of the spin splitting uppermost valence band (UVB) and lowermost conduction (LCB) in bulk atomically thin GaS, GaSe, GaTe, InSe. These layered monochalcogenides appear four major polytypes depending on stacking order, except for monoclinic GaTe. Bulk few-layer $ε$- $γ$-type, odd-number $β$-type InSe crystals are noncentrosymmetric. The splittings UVB LCB near $Γ$-point Brillouin zone finite, but still smaller than those a zinc-blende semiconductor such as GaAs. On other hand, is zero centrosymmetric even-number InSe, owing to constraint spatial inversion symmetry. By contrast, GaTe exhibits because it down single layer. In these monochalcogenide semiconductors, separation non-degenerate bands from adjacent results suppression Elliot-Yafet relaxation mechanism. Therefore, electron- hole-spin times systems with or minimal expected exceed GaAs when D'yakonov-Perel' mechanism also suppressed.