2013/08/20 by Thomas Uehlinger, Gregor Jotzu, Michael Messer +4
Physics and Astronomy · #cond-mat.quant-gas #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.111.185307
published as Phys. Rev. Lett. 111, 185307 (2013) · 11 pages, 10 figures
arxiv created 2013/08/20 · arxiv updated 2013/11/04
We create an artificial graphene system with tunable interactions and study the crossover from metallic to Mott insulating regimes, both in isolated and coupled two-dimensional honeycomb layers. The artificial graphene consists of a two-component spin mixture of an ultracold atomic Fermi gas loaded into a hexagonal optical lattice. For strong repulsive interactions we observe a suppression of double occupancy and measure a gapped excitation spectrum. We present a quantitative comparison between our measurements and theory, making use of a novel numerical method to obtain Wannier functions for complex lattice structures. Extending our studies to time-resolved measurements, we investigate the equilibration of the double occupancy as a function of lattice loading time.