Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 53: Transport: Topological Insulators 3 (jointly with TT, MA)

HL 53.3: Vortrag

Mittwoch, 28. März 2012, 10:00–10:15, BH 334

Fractional quantum Hall states in lattice models and their potential realization due to multiple orbitals — •Stefanos Kourtis, Jörn Venderbos, Jeroen van den Brink, and Maria Daghofer — Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany

It has been recently demonstrated that topologically non-trivial lattice models of interacting particles can lead to a fractional quantum Hall effect without a magnetic field as long as the band width is very narrow. This has triggered a search for possible realizations of such models in optical lattices or materials. One promising observation is that electronic orbital degrees of freedom can lead to the nearly flat bands needed for a fractional-quantum Hall ground state [1]. We map the topologically non-trivial band of such a multi-orbital system onto an effective lattice model [2]. We use exact diagonalization to obtain the ground state of the effective model taking into account Coulomb interactions and investigate its topological properties. In particular, we calculate the eigenvalue spectra, ground states and Chern numbers for a variety of filling fractions and obtain clear indications of a hierarchy of fractionally charged excitations.
J. W. F. Venderbos, M. Daghofer and J. van den Brink, Phys. Rev. Lett. 107, 116401 (2011).
Jörn W.F. Venderbos, Stefanos Kourtis, Jeroen van den Brink and Maria Daghofer, arXiv:1109.5955 (2011).