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Pseudogap at hot spots in the two-dimensional Hubbard model at weak coupling

Daniel Rohe·Walter Metzner
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Abstract

We analyze the interaction-induced renormalization of single-particle excitations in the two-dimensional Hubbard model at weak coupling using the Wick-ordered version of the functional renormalization group. The self energy is computed for real frequencies by integrating a flow equation with renormalized two-particle interactions. In the vicinity of hot spots, that is points where the Fermi surface intersects the umklapp surface, self energy effects beyond the usual quasi-particle renormalizations and damping occur near instabilities of the normal, metallic phase. Strongly enhanced renormalized interactions between particles at different hot spots generate a pronounced low-energy peak in the imaginary part of the self energy, leading to a pseudogap-like double-peak structure in the spectral function for single-particle excitations.

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Daniel Rohe, Walter Metzner. 2005-03-31. Pseudogap at hot spots in the two-dimensional Hubbard model at weak coupling. https://doi.org/10.1103/physrevb.71.115116

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