Department of Physics and Astronomy, University of California, Riverside, California 92521, United States.
Nano Lett. 2012 Jul 11;12(7):3443-7. doi: 10.1021/nl301567n. Epub 2012 Jun 28.
Graphene is an attractive material for spintronics due to theoretical predictions of long spin lifetimes arising from low spin-orbit and hyperfine couplings. In experiments, however, spin lifetimes in single-layer graphene (SLG) measured via Hanle effects are much shorter than expected theoretically. Thus, the origin of spin relaxation in SLG is a major issue for graphene spintronics. Despite extensive theoretical and experimental work addressing this question, there is still little clarity on the microscopic origin of spin relaxation. By using organic ligand-bound nanoparticles as charge reservoirs to tune the mobility between 2700 and 12 000 cm(2)/(V s), we successfully isolate the effect of charged impurity scattering on spin relaxation in SLG. Our results demonstrate that, while charged impurities can greatly affect mobility, the spin lifetimes are not affected by charged impurity scattering.
石墨烯由于其低自旋轨道和超精细耦合理论预测的长自旋寿命，成为自旋电子学中很有吸引力的材料。然而，在实验中，通过 Hanle 效应测量的单层石墨烯 (SLG) 的自旋寿命比理论预期的要短得多。因此，SLG 中的自旋弛豫的起源是石墨烯自旋电子学的一个主要问题。尽管有大量的理论和实验工作致力于解决这个问题，但对于自旋弛豫的微观起源仍然没有明确的认识。通过使用有机配体结合的纳米粒子作为电荷储库，将迁移率在 2700 和 12000 cm2/（Vs）之间调节，我们成功地分离了 charged impurity scattering 对 SLG 中自旋弛豫的影响。我们的结果表明，虽然 charged impurities 会极大地影响迁移率，但自旋寿命不受 charged impurity scattering 的影响。
