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TT: Fachverband Tiefe Temperaturen

TT 76: Graphene: Applications, Luminescence, and Spin Relaxation (jointly with HL, O)

TT 76.8: Vortrag

Mittwoch, 18. März 2015, 18:30–18:45, ER 270

Spin Relaxation in Graphene — •Frank Ortmann¹, Dinh. V. Tuan², David Soriano², Sergio O. Valenzuela^2,3, and Stephan Roche^2,3 — ¹Institute for Materials Science and Dresden Center for Computational Materials Science, TU Dresden, Germany — ²ICN2 Barcelona, Spain — ³ICREA, Barcelona, Spain

Spin polarization of electrons in graphene has been under great attention in recent years due to intrinsically small spin-orbit coupling and hyperfine interaction and high carrier mobilities. However, experimental spin-relaxation times are 3-4 orders of magnitude too short compared to theoretical predictions. Such discrepancy, together with contradictory proposals for spin-relaxation mechanisms, triggered a debate about its behavior in clean and/or defective graphene.

We observe an intrinsic spin-dephasing mechanism in graphene that is most strongly impacting the Dirac point, which can be enhanced by the adsorption of heavy ad-atoms.[1] The extracted spin relaxation times (τ_s) from our simulations show good agreement with experimentally observed energy dependencies of τ_s.

[1] D. V. Tuan, F. Ortmann et al. Nature Phys. 10, 857 (2014).