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arXiv · 0710.3852

Quantum Antiferromagnetism of Fermions in Optical Lattices with Half-filled p-band

Kai Wu·Hui Zhai
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Abstract

We study Fermi gases in a three-dimensional optical lattice with five fermions per site, i.e. the s-band is completely filled and the p-band with three-fold degeneracy is half filled. We show that, for repulsive interaction between fermions, the system will exhibit spin-3/2 antiferromagnetic order at low temperature. This conclusion is obtained in strong interaction regime by strong coupling expansion which yields an isotropic spin-3/2 Heisenberg model, and also in weak interaction regime by Hatree-Fock mean-field theory and analysis of Fermi surface nesting. We show that the critical temperature for this antiferromagnetism of a p-band Mott insulator is about two orders of magnitudes higher than that of an $s$-band Mott insulator, which is close to the lowest temperature attainable nowadays.

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Kai Wu, Hui Zhai. 2008-07-16. Quantum Antiferromagnetism of Fermions in Optical Lattices with Half-filled p-band. https://doi.org/10.1103/physrevb.77.174431

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