Spin splitting in 2D monochalcogenide semiconductors.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Layered monochalcogenides (GaS, GaSe, GaTe, InSe) exhibit diverse polytypes and symmetries.
• Understanding spin properties in these materials is crucial for spintronics.

Purpose of the Study:

• To investigate the spin splitting of the uppermost valence band (UVB) and lowermost conduction band (LCB) in bulk and thin films of GaS, GaSe, GaTe, and InSe.
• To compare spin splitting in these materials with conventional semiconductors like GaAs.

Main Methods:

• Ab initio calculations were employed to determine spin splitting.
• Analysis focused on the Γ-point in the Brillouin zone.

Main Results:

• Noncentrosymmetric GaS, GaSe, and InSe (bulk and few-layer) show finite but smaller spin splittings than GaAs.
• Centrosymmetric materials (including GaTe down to a single layer) exhibit zero spin splitting.
• Band separation suppresses the Elliot-Yafet spin relaxation mechanism.

Conclusions:

• Layered monochalcogenides offer suppressed spin relaxation mechanisms.
• Zero or minimal spin splitting in these materials suggests longer electron and hole spin relaxation times compared to GaAs.
• Potential for advanced spintronic devices.