Giant tunable spin Hall angle in sputtered Bi₂Se₃ controlled by an electric field

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Spin Hall angle is crucial for energy-efficient spintronic devices.
• Bismuth selenide (Bi2Se3) exhibits a large intrinsic spin Hall angle, enabling strong spin-orbit torques.

Purpose of the Study:

• To demonstrate effective and reversible tuning of the spin Hall angle in Bi2Se3.
• To achieve significant enhancement of the spin Hall angle using low power methods.

Main Methods:

• Applying a bipolar electric field across a piezoelectric substrate to tune Bi2Se3.
• Investigating the effects of charge doping and piezoelectric strain on spin properties.

Main Results:

• Achieved a reversible enhancement of the spin Hall angle in Bi2Se3 by approximately 600%.
• Demonstrated asymmetric tuning of the spin Hall angle via electric field application.

Conclusions:

• Electric field-induced charge doping and piezoelectric strain enhance the spin Hall angle by modifying spin Berry curvature.
• This work provides a pathway for developing tunable, low-power spintronic devices.