Anisotropy-driven spin relaxation in germanium
Pengke Li1, Jing Li2, Lan Qing3
1Department of Physics and Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742, USA and Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627, USA.
Physical Review Letters
|February 4, 2014
Summary
Researchers discovered a new spin depolarization mechanism in germanium (Ge) devices. This finding allows for precise measurement of spin lifetimes, revealing exceptionally long spin coherence times at low temperatures.
Area of Science:
- Solid State Physics
- Materials Science
- Quantum Information Science
Background:
- Spin transport in semiconductors is crucial for spintronics.
- Understanding spin depolarization mechanisms is key to preserving spin information.
- Germanium (Ge) is a promising material for spintronic applications.
Purpose of the Study:
- To investigate spin depolarization mechanisms in germanium.
- To develop a method for extracting spin lifetime without spin precession.
- To measure long spin lifetimes in germanium devices.
Main Methods:
- Spin-transport measurements on long-distance germanium devices.
- Application of a magnetic field longitudinal to the initial spin orientation.
- Analysis of electron-phonon scattering and intervalley scattering effects.
Main Results:
- A novel spin depolarization mechanism involving g-factor anisotropy and intervalley scattering was identified.
- Spin lifetime was extracted solely from spin-valve measurements, independent of spin precession.
- Spin lifetimes in germanium reached several hundreds of nanoseconds at low temperatures, exceeding previous experimental results.
Conclusions:
- The discovered mechanism provides new insights into spin dynamics in germanium.
- The developed method enables accurate determination of spin lifetimes under electric-field-induced carrier heating.
- The exceptionally long spin lifetimes in germanium pave the way for advanced spintronic devices.
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