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Spin relaxation by transient monopolar and bipolar optical orientation
B N Murdin1, K Litvinenko, D G Clarke
1Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom.
Physical Review Letters
|April 12, 2006
Summary
We measured electron spin relaxation in semiconductors using time-resolved spectroscopy. Spin relaxation time increased significantly with photogenerated holes, showing potential for spintronic applications.
Area of Science:
- Solid State Physics
- Materials Science
- Quantum Mechanics
Background:
- Electron spin polarization is crucial for spintronics.
- Understanding spin relaxation mechanisms in semiconductors is essential for device development.
Purpose of the Study:
- To investigate the effect of photogenerated holes on electron spin relaxation times in bulk semiconductors.
- To measure spin relaxation using time-resolved spectroscopy and resonant induced Faraday rotation.
Main Methods:
- Utilized two-color time-resolved spectroscopy.
- Employed circularly polarized pump beam for spin polarization induction via direct or Drude absorption.
- Measured spin relaxation times with picosecond resolution using resonant induced Faraday rotation.
Main Results:
- Electron spin relaxation time increased in the presence of photogenerated holes.
- In n-InSb, spin relaxation time extended from 14 ps to 38 ps.
- This effect was observed for both direct band gap excitation and sub-band gap Drude absorption.
Conclusions:
- Photogenerated holes significantly influence and prolong electron spin relaxation in bulk semiconductors.
- The findings suggest potential for controlling spin lifetimes in semiconductor materials for spintronic applications.
- Time-resolved spectroscopy provides a powerful tool for probing ultrafast spin dynamics.
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