Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 3: Graphene: Magnetic Fields (jointly with DS, HL, MA, and TT)

O 3.5: Vortrag

Montag, 11. März 2013, 10:30–10:45, H17

Functionalized Graphene in Quantizing Magnetic Field: The case of bunched impurities — •Peter Silvestrov — Dahlem Center for Complex Quantum Systems, Freie Universitaet Berlin, 14195 Berlin, Germany

Covalent bonding of impurity atoms to graphene, in many cases leads to creation of unusual (singular) zero energy localized electron states. Existence of such states would lead to interesting phenomena, actively discussed recently.

In this talk I consider the behavior of localized impurity levels in graphene in quantizing magnetic field. In the magnetic field the impurity level effectively hybridizes with one of the n=0 Landau level states and splits into two close opposite-energy states. In turn, mixing of localized and Landau levels changes a spin content of a quantum Hall ferromagnet and modifies, via the exchange interaction, the spectrum of electrons surrounding the impurity.

Existing theories investigate graphene uniformly covered by adatoms, though some experiments indicate the tendency towards their clusterization. To address this "unpleasant" possibility, I consider the case of a dense bunch of the impurity atoms, and show how such bunch changes dynamics and spin polarization of a large dense electron droplet surrounding it.