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arXiv · 1308.4401

Artificial graphene with tunable interactions

Thomas Uehlinger·Gregor Jotzu·Michael Messer·Daniel Greif·Walter Hofstetter·Ulf Bissbort·Tilman Esslinger
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Abstract

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.

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Thomas Uehlinger, Gregor Jotzu, Michael Messer, Daniel Greif, Walter Hofstetter, Ulf Bissbort, Tilman Esslinger. 2013-08-20. Artificial graphene with tunable interactions. https://doi.org/10.1103/physrevlett.111.185307

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