High Field Phase Diagram of Cuprates Derived from the Nernst Effect

Measurements of the Nernst signal in the vortex-liquid state of the cuprates to high fields (33 T) reveal that vorticity extends to very high fields even close to the zero-field critical temperature [Formula presented]. In overdoped [Formula presented], we show that the upper critical field [Formula presented] curve does not end at [Formula presented], but at a much higher temperature. These results imply that [Formula presented] corresponds to a loss in phase rigidity rather than a vanishing of the pairing amplitude. An intermediate field [Formula presented] is shown to be the field scale for the flux-flow resistivity.