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Spin relaxation in single-layer and bilayer graphene
1Department of Physics and Astronomy, University of California, Riverside, California 92521, USA.
Physical Review Letters
|August 27, 2011
Summary
Single-layer graphene (SLG) shows Elliot-Yafet spin relaxation, while bilayer graphene (BLG) exhibits Dyakonov-Perel spin relaxation due to differences in screening and surface sensitivity. This study reveals contrasting spin dynamics in graphene layers.
Area of Science:
- Condensed matter physics
- Materials science
- Spintronics
Background:
- Spin relaxation mechanisms are crucial for spintronic device functionality.
- Graphene's unique electronic properties make it a promising material for spintronics.
- Understanding spin relaxation in single-layer graphene (SLG) and bilayer graphene (BLG) is essential for device optimization.
Purpose of the Study:
- To investigate and compare spin relaxation mechanisms in SLG and BLG.
- To determine the dominant spin relaxation pathways in each type of graphene.
- To elucidate the role of screening and surface sensitivity in spin relaxation.
Main Methods:
- Experimental investigation of spin relaxation in graphene spin valves.
- Measurement of spin lifetime (τ(s)) and momentum scattering time (τ(p)).
- Analysis of the dependence of τ(s) on carrier concentration in SLG and BLG.
Main Results:
- SLG exhibits a linear relationship between τ(s) and τ(p), indicating dominant Elliot-Yafet (EY) spin relaxation.
- BLG shows an inverse dependence between τ(s) and τ(p), suggesting dominant Dyakonov-Perel spin relaxation.
- Enhanced screening and reduced surface sensitivity in BLG suppress impurity-induced EY spin relaxation.
Conclusions:
- Spin relaxation mechanisms differ significantly between SLG and BLG.
- Elliot-Yafet relaxation dominates in SLG, while Dyakonov-Perel relaxation prevails in BLG at low temperatures.
- Graphene's structural properties critically influence spin dynamics, impacting spintronic applications.
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