Unveiling the Role of Spin Currents on the Giant Rashba Splitting in Single-Layer WSe₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Rashba spin splitting is crucial for spintronic applications in inversion-asymmetric materials.
• Kohn-Sham density functional theory (DFT) with standard approximations often underestimates this effect.
• Spin currents (J⃗) are known to modify many-body interactions, a factor typically missed by DFT.

Purpose of the Study:

• To investigate the giant Rashba splitting in single-layer WSe2.
• To quantify the impact of including spin currents within a spin current DFT (SCDFT) framework.
• To demonstrate SCDFT's capability in accurately modeling Rashba effects.

Main Methods:

• Utilized spin current density functional theory (SCDFT) to model electronic states.
• Investigated single-layer WSe2 as a model system.
• Quantified the contribution of spin currents to the Rashba splitting.

Main Results:

• SCDFT successfully captures the giant Rashba band splitting in single-layer WSe2.
• Standard DFT approximations systematically underestimated the Rashba splitting.
• Inclusion of spin currents (J⃗) in density functional approximations (DFAs) increased the Rashba splitting by approximately 20%.

Conclusions:

• SCDFT provides a more accurate theoretical framework for modeling Rashba spin splitting compared to standard DFT.
• The inclusion of spin currents is essential for precise predictions in spintronic materials.
• This work highlights the importance of SCDFT for understanding and designing materials for spintronics.