Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 103: Transport: Poster Session

TT 103.32: Poster

Thursday, March 19, 2015, 15:00–18:00, Poster B

Effect of Hydrogen on Spin-Transport in Graphene — •Fedor Tkatschenko, Jan Bundesmann, Denis Kochan, Jaroslav Fabian, and Klaus Richter — Institut für Theoretische Physik, Universität of Regensburg, 93053 Regensburg Germany

The impact of hydrogen on the spin lifetime is expected to be huge, as it leads to resonant scattering near the charge neutrality point [1] and to the formation of local magnetic moments in the vicinity of the hydrogen. This situation strongly enhances the spin flip probability of electrons and holes when passing through a graphene sample.

Here we aim to explain the experimental results [2], which seem to contradict the theoretical predictions, by taking into account the formation of hydrogen clusters, which reduce the effect on the spin lifetime compared to isolated hydrogen atoms. We calculate the electronic structure of hydrogenated graphene and perform quantum transport calculations based on a tight-binding model. Adopting the parameters from ab initio calculations, we find that clustering affects both, the formation of the resonant state and the magnetic moments. We show that the exact configuration, such as the sublattice occupation of each cluster is essential, as it decides for example if local magnetic moments are formed and determines the position of the resonant state.

[1] D. Kochan, M. Gmitra and J. Fabian PRL 112, 116602 (2014)

[2] M. Wojtaszeck, I. J. Vera-Marun, T. Massen and B. J. van Wees

   PRB 87, 081402(R) (2013)