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arXiv · 1205.4026

Mott criticality and pseudogap in Bose-Fermi mixtures

Ehud Altman·Eugene Demler·Achim Rosch
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Abstract

We study the Mott transition of a mixed Bose-Fermi system of ultracold atoms in an optical lattice, where the number of (spinless) fermions and bosons adds up to one atom per lattice, n_F+n_B=1. For weak interactions, a Fermi surface coexists with a Bose-Einstein condensate while for strong interaction the system is incompressible but still characterized by a Fermi surface of composite fermions. At the critical point, the spectral function of the fermions, A(k,w), exhibits a pseudo-gapped behavior, rising as |w| at the Fermi momentum, while in the Mott phase it is fully gapped. Taking into account the interaction between the critical modes leads at very low temperatures either to p-wave pairing or the transition is driven weakly first order. The same mechanism should also be important in antiferromagnetic metals with a small Fermi surface.

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Ehud Altman, Eugene Demler, Achim Rosch. 2012-07-20. Mott criticality and pseudogap in Bose-Fermi mixtures. https://doi.org/10.1103/physrevlett.109.235304

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