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Spin polarized electron transport near the Si/SiO2 interface
1Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, Maryland 20742 USA.
Physical Review Letters
|October 2, 2009
Summary
Investigating spin transport near silicon interfaces reveals that electrostatic gating shortens spin transit times and enhances spin coherence. This counterintuitive behavior is attributed to strong interface-induced spin depolarization effects.
Area of Science:
- Condensed matter physics
- Materials science
- Spintronics
Background:
- Understanding spin transport in semiconductor interfaces is crucial for spintronic device development.
- The interface between silicon (Si) and silicon dioxide (SiO2) is a fundamental system in electronics.
Purpose of the Study:
- To investigate spin transport dynamics near the Si/SiO2 interface using lateral devices.
- To analyze the impact of electrostatic gating on spin polarization, transit time, and coherence.
Main Methods:
- Spin-valve measurements in an in-plane magnetic field.
- Spin precession measurements in a perpendicular magnetic field at 60 K.
- Application of an electrostatic gate to attract electrons to the interface.
Main Results:
- Gating reduced average spin transit times and increased spin coherence near the interface.
- Observed behavior contrasted with expected exponential depolarization in bulk transport.
- Identified strong interface-induced spin depolarization, reducing spin lifetime by over two orders of magnitude.
Conclusions:
- Interface effects significantly alter spin transport properties compared to bulk silicon.
- Electrostatic gating can manipulate spin dynamics at the Si/SiO2 interface.
- Understanding interface depolarization is key to controlling spin coherence in Si-based spintronic devices.
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