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Remnant Fermi surface in a pseudogap regime of the two-dimensional Hubbard model at finite temperature

Taiichiro Saikawa·Alvaro Ferraz
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Abstract

A precursor effect on the Fermi surface in the two-dimensional Hubbard model at finite temperatures near the antiferromagnetic instability is studied using three different itinerant approaches: the second order perturbation theory, the paramagnon theory (PT), and the two-particle self-consistent (TPSC) approach. In general, at finite temperature, the Fermi surface of the interacting electron systems is not sharply defined due to the broadening effects of the self-energy. In order to take account of those effects we consider the single-particle spectral function $A({\bf k},0)$ at the Fermi level, to describe the counterpart of the Fermi surface at T=0. We find that the Fermi surface is destroyed close to the pseudogap regime due to the spin-fluctuation effects in both PT and TPSC approaches. Moreover, the top of the effective valence band is located around ${\bf k}=(π/2,π/2)$ in agreement with earlier investigations on the single-hole motion in the antiferromagnetic background. A crossover behavior from the Fermi-liquid regime to the pseudogap regime is observed in the electron concentration dependence of the spectral function and the self-energy.

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Taiichiro Saikawa, Alvaro Ferraz. 2001-04-09. Remnant Fermi surface in a pseudogap regime of the two-dimensional Hubbard model at finite temperature. https://arxiv.org/abs/cond-mat/9909355

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