arXiv:1604.00096 · Physical Review Letters

Observation of 2D Fermionic Mott Insulators of K 40 with Single-Site Resolution

Lawrence W. Cheuk, Matthew A. Nichols, Katherine R. Lawrence, Melih Okan, Hao Zhang, Martin W. Zwierlein

Published Jun 10, 2016• 103 citations

Abstract

We report on the site-resolved observation of characteristic states of the two-dimensional repulsive Fermi-Hubbard model, using ultracold ^{40}K atoms in an optical lattice. By varying the tunneling, interaction strength, and external confinement, we realize metallic, Mott-insulating, and band-insulating states. We directly measure the local moment, which quantifies the degree of on-site magnetization, as a function of temperature and chemical potential. Entropies per particle as low as 0.99(6)k_{B} indicate that nearest-neighbor antiferromagnetic correlations should be detectable using spin-sensitive imaging.

DOI: 10.1103/physrevlett.116.235301

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