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.