Hot Spots and Pseudogaps for Hole- and Electron-Doped High-Temperature Superconductors

Using cluster perturbation theory, it is shown that the spectral weight and pseudogap observed at the Fermi energy in recent angle resolved photoemission spectroscopy of both electron- and hole-doped high-temperature superconductors find their natural explanation within the $t\mathrm{\text{−}}{t}^{\prime }\mathrm{\text{−}}{t}^{\prime \prime }\mathrm{\text{−}}U$ Hubbard model in two dimensions. The value of the interaction $U$ needed to explain the experiments for electron-doped systems at optimal doping is in the weak to intermediate coupling regime where the $t\mathrm{\text{−}}J$ model is inappropriate. At strong coupling, short-range correlations suffice to create a pseudogap, but at weak-coupling long correlation lengths associated with the antiferromagnetic wave vector are necessary.