Spectral function and photoemission spectra in antiferromagnetically correlated metals

Antiferromagnetic spin fluctuations in a two-dimensional metal, such as doped high-T₂ superconductors, lead to a pseudogap in the electronic spectrum. In the spectral function weight is shifted from the single quasiparticle peak of the Fermi-liquid regime to the incoherent particle and hole backgrounds, which evolve into the upper and lower Mott-Hubbard bands of the antiferromagnetic insulator. Precursors of these split bands show up as ``shadow bands'' in angle-resolved photoemission spectra.