Pseudogap and antiferromagnetic correlations in the Hubbard model

TL;DR

This paper investigates the pseudogap phenomenon in the Hubbard model with next-nearest neighbor hopping, revealing that long-range antiferromagnetic correlations cause the pseudogap in electron-doped systems, with the effects of $t'$ influencing local spectral features.

Contribution

It demonstrates how long-range antiferromagnetic correlations induce the pseudogap and explores the impact of next-nearest neighbor hopping on spectral properties in the Hubbard model.

Findings

Pseudogap along the zone diagonal is due to long-range antiferromagnetic correlations.

Short-range correlations produce a pseudogap in magnetic susceptibility and a gap near (π,π/2).

Effect of $t'$ on low-energy ARPES spectra is weak except near the zone edge.

Abstract

Using the dynamical cluster approximation and quantum monte carlo we calculate the single-particle spectra of the Hubbard model with next-nearest neighbor hopping $t'$. In the underdoped region, we find that the pseudogap along the zone diagonal in the electron doped systems is due to long range antiferromagnetic correlations. The physics in the proximity of $(0,\pi)$ is dramatically influenced by $t'$ and determined by the short range correlations. The effect of $t'$ on the low energy ARPES spectra is weak except close to the zone edge. The short range correlations are sufficient to yield a pseudogap signal in the magnetic susceptibility, produce a concomitant gap in the single-particle spectra near $(\pi,\pi/2)$ but not necessarily at a location in the proximity of Fermi surface.