Artificial graphene with tunable interactions.
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.
Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland.
Thomas
T
Uehlinger
Gregor
G
Jotzu
Michael
M
Messer
Daniel
D
Greif
Walter
W
Hofstetter
Ulf
U
Bissbort
Tilman
T
Esslinger