Pseudogap and Antiferromagnetic Correlations in the Hubbard Model

Using the dynamical cluster approximation and quantum Monte Carlo simulations 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, π) is dramatically influenced by t^′ and determined by the short range correlations. The effect of t^′ on the low-energy angle-resolved photoemission spectroscopy spectra is weak except close to the zone edge. The short range correlations are sufficient to yield a pseudogap signal in the magnetic susceptibility and produce a concomitant gap in the single-particle spectra near (π, π/2), but not necessarily at a location in the proximity of the Fermi surface.