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DS: Fachverband Dünne Schichten
DS 22: 2D semiconductors and van der Waals heterostructures V (joint session HL/DS/O)
DS 22.1: Vortrag
Mittwoch, 18. März 2020, 09:30–09:45, POT 81
Impurity effects in graphene: resonances, localized states and Mott-transitions — Yuriy G. Pogorelov1, •Denis Kochan2, and Vadim M. Loktev3 — 11IFIMUP-IN, Departamento de Física, Universidade do Porto, Porto, Portugal — 2Institute for Theoretical Physics, University of Regensburg, Regensburg, Germany — 3N.N. Bogolyubov Institute of Theoretical Physics, NAS of Ukraine, Kyiv, Ukraine
Impurities modify electronic spectrum of graphene in several ways. For example, they can shift charge neutrality point, tilt the Fermi level, open spectral (quasi)gaps, form resonances, and localized states.
In the presentation we discuss formation of resonances, and localized states in graphene for Anderson-like impurities (Hydrogen, Copper, Fluorine) in top, bridge and hollow positions. Particularly, we focus on spectral transition between resonant and localized states, and Mott mobility edges, tracing dependencies on graphene Fermi energy, concentration of impurities, their sub-lattices distribution, and impurity hybridization strength.
Employing the group expansion of the Green’s functions we calculated reconstructed band structure of graphene hosting Anderson impurities. Applying Ioffe-Regel-Mott criterion, we obtained system-specific critical concentrations at which system undergoes resonance-to-bound-state transition.