Regensburg 2013 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 30: Quantum Chaos II

DY 30.1: Vortrag

Donnerstag, 14. März 2013, 15:00–15:15, H47

Edge-independent formation of localized states in manipulated honeycomb lattices — •Pia Adam and Martina Hentschel — Institut für Physik, Technische Universität Ilmenau, Germany

We investigate finite hexagonal lattice systems with different boundary conditions under the influence of strain and local deformations. To this end, we use a tight-binding model including up to third nearest neighbor coupling. This model allows us to describe real graphene as well as honeycomb photonic crystals. First, we study the effect of unidirectional strain by varying the nearest neighbor coupling in one direction. In a microwave realisation of this problem with armchair boundary conditions a phase transition under increasing strain from a gapless to a gapped phase is predicted and observed. Moreover, localized states form at the edges perpendicular to the strain on a hexagon with armchair edges [1]. We confirm these results and, in particular, find them to hold for zigzag edges as well, i.e. to be independent of the edge termination. Furthermore, we investigate the effect of local deformations simulated by locally changing the nearest neighbor interaction. This leads to states which are strongly localized at the sites adjacent to the deformed bonds with energies at the low and high energy flanks of the spectrum rather than near the Dirac point.

[1] M. Bellec, U. Kuhl, G. Montambaux, F. Mortessagne, arXiv:1210.4642 [cond-mat.mes-hall].