Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 82: Low-Dimensional Systems: Topological Order (organized by TT)
TT 82.3: Talk
Thursday, April 3, 2014, 10:00–10:15, HSZ 204
Conductance of flat bands with long range Coulomb interactions — •Wolfgang Häusler — Institut für Physik, Universität Augsburg, D-86135 Augsburg
Dispersionless (“flat") electronic bands can arise throughout the Brillouin zone in certain multipartite lattices, besides ordinary dispersing bands. In such a flat band, hoppings between atomic orbitals interfere destructively which then leads to localization, a phenomenon denoted as “caging" of carriers. As a consequence, the system is insulating at zero temperature even when this band is partly filled, provided all other bands are either empty or completely filled.
One may ask whether long range Coulomb interactions can alter this situation and cause finite conductivity. In the absence of kinetic energy, flat band carriers tend to Wigner crystallize. Here, this general observation is analyzed for the two-dimensional case specifically for the Sutherland or T3–lattice where a conductivity is found, depending non-trivially on the carrier density at small flat band fillings.