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TT: Fachverband Tiefe Temperaturen
TT 49: CE: Spin Systems and Itinerant Magnets 2
TT 49.5: Talk
Thursday, March 17, 2011, 15:00–15:15, HSZ 03
Numerical studies of the metallic and insulating phases of a spinless fermion model on a kagome lattice — Aroon O'Brien1, Frank Pollmann1, •Satoshi Nishimoto2, Masaaki Nakamura3, and Peter Fulde1,4 — 1Max Planck Institute for the Physics of Complex Systems, Noethnitzer Strasse 38, 01187 Dresden, Germany — 2IFW Dresden, Leibniz Institute for Solid State and Materials Research, 01069 Dresden, Germany — 3Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan — 4Asia Pacific Center for Theoretical Physics, Pohang, Korea
Geometrically frustrated models exhibit many fascinating physical properties such as highly degenerate ground states and even the possible existence of fractionally charged excitations. Both phenomena are consequences of the frustrated electronic interactions.
We present a model of spinless fermions on the 2D kagome lattice. In this model a metal-insulator transition occurs as nearest-neighbour interactions are tuned into the strongly correlated regime. We consider the nature of the transition for positive and negative hopping matrix elements; differences between the two cases are attributable to the form of the band structure.
In the insulating phase fractionally charged excitations occur at certain filling factors. An investigation of the dynamical properties of the fractional charges is discussed. Particular focus is given to signatures of the confined collective excitations as observed in numerically calculated spectral densities.