Unconventionally large quantum-dissipative gap regime in overdoped (formula presented)

We report on an unexpectedly extensive dissipative gapped regime in the zero-temperature (quantum) limit in highly overdoped (formula presented) Using high-field interlayer resistivity measurements we show that as (formula presented) the magnetic field that closes the pseudogap and the upper critical field (formula presented) coincide, uniquely defining the upper limit on the vortex state. By mapping the upper and lower bounds on the molten vortex state, we find the gapped quantum fluctuation regime stretching from (formula presented) to 70 T. This exceeds by far the conventional estimates, pointing to the anomalous gapped nature of the strongly overdoped regime. © 2003 The American Physical Society.