Pseudogaps and Their Interplay with Magnetic Excitations in the Doped 2D Hubbard Model

On the basis of quantum Monte Carlo simulations of the two-dimensional Hubbard model which cover the doping range from the underdoped to the overdoped regime, we find that the single-particle spectral weight A(→k,ω) qualitatively reproduces both the momentum ( d_x²-y² symmetry) and doping dependence of the pseudogap as found in photoemission experiments. The drastic doping dependence of the spin response χₛ(→q,ω), which is sharp in both →q[≈(π,π)] and ω in the underdoped regime but broad and structureless otherwise, identifies remnants of the antiferromagnetic order as the driving mechanism behind the pseudogap and its evolution with doping.