Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Graphene II
O 42.4: Vortrag
Mittwoch, 16. März 2011, 12:00–12:15, WIL B321
(contribution withdrawn) Charged collective excitations and SU(4) symmetry in graphene — •Andrea Fischer1, Rudolf Römer1, and Alexander Dzyubenko2,3 — 1University of Warwick, Coventry, UK — 2California State University Bakersfield, California, US — 3General Physics Institute, Russian Academy of Sciences, Moscow, Russia
We show that graphene in a strong magnetic field with partially filled Landau levels sustains charged collective excitations, which are bound states of three-particle complexes [1]. Some of these states are optically bright and may be detected in spectroscopy experiments, enhancing the current understanding of electron-electron interactions in graphene. Indeed, such states have recently been seen at zero magnetic field in an ARPES study [2]. The states can be classified using the geometrical symmetries - non-commutative magnetic translations and generalized rotations - in addition to the dynamical SU(4) symmetry in graphene. From the SU(4) symmetry point of view, such excitations are analogous to bound states of two quarks and one antiquark with four flavours. Using Young diagram techniques, we determine the multiplet structure and establish a flavour optical selection rule to identify the bright states for experimental studies.
[1] A.M. Fischer, R.A. Römer and A.B. Dzyubenko, arXiv: 1005.3277
[2] A. Bostwick et al., Science 328, 999 (2010)