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Published on: June 28, 2018
Introduction to spin-polarized ballistic hot electron injection and detection in silicon
1Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, MD 20742, USA. appelbaum@physics.umd.edu
Summary
Ballistic hot electron transport in semiconductors offers a novel solution for spin injection and detection. This method achieves long spin lifetimes and high spin coherence, overcoming previous limitations in spintronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Spintronics
Background:
- Spin injection in semiconductors faces challenges due to conductivity and spin lifetime mismatches.
- Ferromagnetic ohmic contacts limit the efficiency of spin injection in semiconductor devices.
- Existing methods struggle to maintain spin coherence over transport distances.
Purpose of the Study:
- To investigate ballistic hot electron transport as a method for overcoming spin injection limitations in semiconductors.
- To explore the use of spin-dependent mean free path in ferromagnetic films for spin detection.
- To analyze spin lifetime and coherence in silicon-based devices utilizing drift-dominated transport.
Main Methods:
- Experimental techniques including spin precession and spin-valve measurements on silicon-based devices.
- Development of a quantitative model to simulate device characteristics for undoped and doped spin transport channels.
- Application of the model to determine spin current velocity, diffusion constant, and spin lifetime.
Main Results:
- Ballistic hot electron transport successfully overcomes conductivity and spin lifetime mismatches.
- Demonstration of spin detection through the spin dependence of the mean free path.
- Observation of exceptionally long spin lifetime and high spin coherence in silicon devices.
- Development of a model enabling a spin 'Haynes-Shockley' experiment without time-of-flight techniques.
Conclusions:
- Ballistic hot electron transport is a viable approach for efficient spin injection and detection in semiconductors.
- Drift-dominated transport in semiconductors leads to enhanced spin lifetime and coherence.
- The developed quantitative model accurately simulates device characteristics and provides key spin transport parameters.
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