Laser-Induced Spin Precession in Topological Insulator Devices

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Spintronics

Background:

• Controlling spin currents in topological insulators (TIs) is essential for spintronics.
• The robust chiral edge states in TIs hinder spin manipulation for devices like spin-field effect transistors (SFETs).

Purpose of the Study:

• To theoretically demonstrate a method for overcoming the challenge of spin manipulation in TIs.
• To achieve controllable spin-polarized photocurrents in a driven 2D TI system.

Main Methods:

• The study employs theoretical modeling of a 2D topological insulator.
• Synergistic application of circularly polarized light and gate-tunable Rashba spin-orbit coupling (rSOC).
• Exploitation of Floquet sidebands generated by laser irradiation.

Main Results:

• Demonstrated controllable spin precession induced by rSOC within Floquet sidebands.
• Generated one-way, switchable spin-polarized photocurrents, a non-equilibrium effect.
• Achieved SFET functionality within a driven TI operating in a Floquet replica.

Conclusions:

• A novel mechanism for light-based control in topological spintronics is proposed.
• This approach offers a new paradigm for manipulating spin currents in TIs.
• The findings open avenues for developing advanced spintronic devices with enhanced functionality.