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Conversion of spin into directed electric current in quantum wells.
S D Ganichev1, E L Ivchenko, S N Danilov
1Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany.
Physical Review Letters
|May 1, 2001
Summary
Circularly polarized light creates spin-polarized currents in quantum wells. This spin polarization drives directed carrier motion, acting like a battery generating a controllable current.
Area of Science:
- Condensed matter physics
- Quantum optics
- Semiconductor spintronics
Background:
- Quantum well structures exhibit unique electronic properties.
- Controlling electron spin states is crucial for spintronics.
- Light-matter interactions can induce spin polarization.
Purpose of the Study:
- To achieve and investigate nonequilibrium spin populations in quantum wells.
- To understand the mechanism of photon helicity-driven currents.
- To demonstrate a spin-polarized current generation system.
Main Methods:
- Applying circularly polarized radiation to quantum well structures.
- Observing and analyzing the directed motion of free carriers.
- Developing a microscopic model for photon helicity-driven currents.
Main Results:
- A nonequilibrium population of spin-up and spin-down states was achieved.
- Spin polarization induced directed carrier motion perpendicular to light propagation.
- The current direction was controlled by light helicity, reversible by switching.
Conclusions:
- Photon helicity can drive a spin-polarized current in quantum wells.
- The system effectively acts as a battery generating spin-polarized current.
- This offers a novel method for controlling electrical currents using light polarization.