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arXiv · 0809.1464

Metallic and Insulating Phases of Repulsively Interacting Fermions in a 3D Optical Lattice

U. Schneider·L. Hackermuller·S. Will·Th. Best·I. Bloch·T. A. Costi·R. W. Helmes·D. Rasch·A. Rosch
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Abstract

The fermionic Hubbard model plays a fundamental role in the description of strongly correlated materials. Here we report on the realization of this Hamiltonian using a repulsively interacting spin mixture of ultracold $^{40}$K atoms in a 3D optical lattice. We have implemented a new method to directly measure the compressibility of the quantum gas in the trap using in-situ imaging and independent control of external confinement and lattice depth. Together with a comparison to ab-initio Dynamical Mean Field Theory calculations, we show how the system evolves for increasing confinement from a compressible dilute metal over a strongly-interacting Fermi liquid into a band insulating state. For strong interactions, we find evidence for an emergent incompressible Mott insulating phase.

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U. Schneider, L. Hackermuller, S. Will, Th. Best, I. Bloch, T. A. Costi, R. W. Helmes, D. Rasch, A. Rosch. 2008-09-09. Metallic and Insulating Phases of Repulsively Interacting Fermions in a 3D Optical Lattice. https://doi.org/10.1126/science.1165449

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