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Scattering theory of current-induced spin polarization
1Physics Department, University of Arizona, 1118 E 4th Street, Tucson, AZ 85721, USA.
Nanotechnology
|June 24, 2010
Summary
We developed a new theory for magnetoelectric effects, revealing large, controllable spin polarizations in mesoscopic systems. These spin polarizations, measured via a probe, exceed known values and show weak correlation with spin currents.
Area of Science:
- Condensed Matter Physics
- Spintronics
- Quantum Transport
Background:
- Magnetoelectric effects offer pathways to control spin properties.
- Spin-orbit coupling in mesoscopic systems is crucial for generating spin polarization.
- Probing local spin polarization requires careful control of electrochemical potentials.
Purpose of the Study:
- To develop a novel scattering theory for magnetoelectrically induced spin polarizations.
- To investigate the measurement of local spin polarizations using an external probe.
- To analyze the statistics and magnitude of these spin polarizations.
Main Methods:
- Construction of a novel scattering theory.
- Utilizing spin-orbit-coupled mesoscopic systems.
- Employing an external probe with controllable electrochemical and spin-dependent chemical potentials.
- Application of random matrix theory for statistical analysis.
Main Results:
- Identified local spin-dependent potentials in the sample with those in the probe under specific conditions.
- Found spin polarizations that are independent of probe contact transparency.
- Demonstrated that single systems exhibit spin polarizations exceeding known current-induced values by a large factor.
- Calculated quantum correlations between spin polarizations and spin currents.
Conclusions:
- The developed theory provides a framework for understanding and quantifying magnetoelectrically induced spin polarizations.
- Large spin polarizations are achievable and measurable in mesoscopic systems.
- These large polarizations show weak correlation with external spin currents, consistent with mesoscopic universality.
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