Tunable Rashba Spin Splitting in Two-Dimensional Polar Perovskites

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) Rashba semiconductors are crucial for nanospintronics due to their structure inversion asymmetry and spin-orbit coupling (SOC).
• Exploring novel 2D materials with strong Rashba effects is essential for advancing spin field-effect transistors (FETs).

Purpose of the Study:

• To investigate the electronic structures and Rashba effect in 2D polar perovskites (ABX3).
• To identify 2D polar perovskites with significant Rashba constants and electric field responses for spintronic applications.

Main Methods:

• First-principles density functional theory (DFT) calculations were employed.
• Systematic investigation of electronic structures and Rashba parameters for various 2D polar perovskite compositions.

Main Results:

• 2D polar perovskites (tetragonal and orthorhombic) exhibit a strong intrinsic Rashba effect near the Γ point.
• 2D orthorhombic RbSnI3 shows the largest Rashba constant (1.176 eV Å), comparable to 3D bulk perovskites.
• Several 2D polar perovskites, including RbPbI3 and CsPbI3, demonstrate strong electric field responses (>0.5 e Ų).

Conclusions:

• 2D polar perovskites are promising candidates for Rashba semiconductors due to their large Rashba constants and electric field responses.
• These materials enable a short spin channel length (tens of nanometers), preserving spin coherence in spin FETs.
• 2D polar perovskites offer superior performance for spin FETs compared to conventional 3D micrometer-scale devices.