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O: Fachverband Oberflächenphysik

O 86: Graphene: Electronic Properties, Structure and Substrate Interaction I

O 86.2: Vortrag

Donnerstag, 23. März 2017, 10:45–11:00, WIL A317

Ab-initio study of the effective Coulomb interactions and Stoner ferromagnetism in hydrogenated graphene — •Ersoy Sasioglu¹, Hanif Hadipour², Christoph Friedrich³, Stefan Blügel³, and Ingrid Mertig¹ — ¹Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 Halle (Saale) Germany — ²Department of Physics, University of Guilan, 41335 Rasht, Iran — ³Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425Jülich, Germany

Hydrogenation provides a novel way to tune the electronic and optical properties of the graphene. Recent scanning tunneling microscopy experiments have demonstrated that local graphene magnetism can be selectively switched on and off by hydrogen dimers [1]. Employing ab-initio calculations in conjunction with the constrained random-phase approximation [2] we study the strength of the effective Coulomb interaction U in hydrogenated graphene. It is found that the calculated U parameters are smaller than the ones in pristine graphene and depend on the hydrogen concentration. Moreover, the U parameters are very sensitive to the position of hydrogen atoms adsorbed on the graphene lattice. We discuss the instability of the paramagnetic state towards the ferromagnetic one on the basis of calculated U parameters within the Stoner model. Spin-polarized calculations reveal that the experimentally observed itinerant ferromagnetism in hydrogenated graphene can be well described by the Stoner model.
H. González-Herrero et al., Science 352, 437 (2016).
E. Şaşioğlu et al., Phys. Rev. B 83, 121101(R) (2011).