Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 53: Quantum Impurities and Kondo Physics
TT 53.4: Vortrag
Mittwoch, 14. März 2018, 10:15–10:30, HFT-FT 131
Numerical Renormalization Group study of Gate Induced Kondo Screening in Graphene — •Daniel May1, Kira Deltenre1, Anika Henke1, Jinhai Mao2, Yuhang Jiang2, Po-Wei Lo3,4, Guohong Li2, Guang-Yu Guo3,4, Frithjof Anders1, and Eva Y. Andrei2 — 1Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, Germany — 2Rutgers University, Department of Physics and Astronomy, USA — 3National Taiwan University, Department of Physics, Taiwan — 4National Center for Theoretical Sciences, Physics Division, Taiwan
Graphene in its pristine form has transformed our understanding of 2D electron systems leading to fundamental discoveries. When graphene’s honeycomb lattice is disrupted by single atom vacancies a gate voltage dependent Kondo effect may emerge. We present numerical renormalization group (NRG) calculations for a realistic two-orbital model consisting of a local σ orbital and a localized π orbital induced by the vacancy. Depending on the graphene curvature in the vicinity of the vacancy, we determine three different regimes. The re-entrance regime is characterized by a conventional Kondo effect (p doping), a breakdown of the Kondo peak close to the Dirac point | µ| → 0, and a underscreened Kondo (n doping) where the π band is screening the magnetic moment of the σ orbital. Changing the hybridization between impurity and band drives the system into a regime where Kondo screening is present for either strong n or p doping.