Pseudogap ground state in high-temperature superconductors

By re-examining recently published photoemission data we demonstrate that the apparent Fermi surface of the pseudogap ground state is a disconnected arc centered on the nodes. This scenario is also consistent with results from Raman spectroscopy and NMR. We also show that it is consistent with doping-dependent entropy data and discuss the origins of this unusual electronic "arc-liquid" state. We show that the pseudogap closes, and the arcs become connected, when the antiferromagnetic (AF) correlation length falls to the size of the lattice parameter. These results are consistent with a picture of Fermi-surface reconstruction due to short-range AF correlations.