Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 58: Poster Session Transport & Matter at Low Temperature
TT 58.41: Poster
Donnerstag, 14. März 2013, 15:00–19:00, Poster D
Kondo effect in graphene with isolated vacancies — •Lars Fritz1 and Andrew Mitchell1,2 — 1Universität zu Köln, Institut für Theoretische Physik — 2Department of Chemistry, Physical and Theoretical Chemistry, Oxford University,UK
The physics of a reconstructed vacancy in graphene is investigated by a combination of numer- ical renormalization group and analytical techniques. The effective model introduced recently by [1] describes a localized σ level hybridized with the π-band, whose local density of states is enhanced due to potential scattering. Rich quantum impurity physics is shown to result, with both doublet and triplet powerlaw Kondo phases accessible, depending on microscopic parameters. Thermodynamic quantities and the scattering t matrix are calculated ex- actly in each phase. The quantum phase transition separating Kondo phases is examined, and the unusual role of particle-hole symmetry breaking is also considered. We show that the asymmetric lo- cal moment phases of simplified Kondo models are not in practice accessible in the full Andersonian model describing the vacancy, and that Kondo screening is always important at low energies.
[1] Cazalilla et al., arXiv:1207.3135 (2012)