Coherence control of Hall charge and spin currents

Area of Science:

• Spintronics
• Optoelectronics
• Solid-state physics

Background:

• Generating and controlling pure spin and charge currents is crucial for next-generation electronic devices.
• Optical techniques offer a promising, field-free method for manipulating charge and spin dynamics in semiconductors.

Purpose of the Study:

• To investigate the generation of pure spin and charge currents in intrinsic gallium arsenide (GaAs) using two-color optical coherence control.
• To demonstrate the ability to tune the type, magnitude, and direction of these currents by manipulating optical parameters.

Main Methods:

• Utilized two-color optical coherence control with orthogonally and parallel polarized femtosecond pulses (70 fs) at 1430 nm and 715 nm.
• Performed experiments at cryogenic temperatures (80 K) in intrinsic GaAs.
• Varied the relative phase and polarization of the incident laser pulses.

Main Results:

• Generated a pure spin source current yielding a transverse Hall pure charge current with orthogonally polarized pulses.
• Generated a pure charge source current yielding a pure spin current with parallel polarized pulses.
• Demonstrated effective tuning of both source and transverse currents' type, magnitude, and direction by adjusting optical parameters.

Conclusions:

• Optical coherence control provides a versatile, field-free method for generating and manipulating pure spin and charge currents in GaAs.
• This technique opens possibilities for novel spintronic device functionalities and optical control of charge/spin dynamics.