TY - JOUR

T1 - Delocalized Quasiparticles in the Vortex State of an Overdoped High- [Formula presented] Superconductor Probed by [Formula presented] NMR

AU - Zheng, G. q.

AU - Ozaki, H.

AU - Kitaoka, Y.

AU - Kuhns, P.

AU - Reyes, A. P.

AU - Moulton, W. G.

PY - 2002

Y1 - 2002

N2 - We report the spin Knight shift ([Formula presented]) and the nuclear spin-lattice relaxation rate ([Formula presented]) in the vortex state as a function of magnetic field ([Formula presented]) up to 28 T in the high- [Formula presented] superconductor [Formula presented] ([Formula presented]). At low temperatures well below [Formula presented], both [Formula presented] and [Formula presented] measured around the middle point between the two nearest vortices (saddle point) increase substantially with increasing field, which indicate that the quasiparticle states with an ungapped spectrum are extended outside the vortex cores in a [Formula presented]-wave superconductor. The density of states (DOS) around the saddle point is found to be [Formula presented], with [Formula presented] and [Formula presented] being the normal-state DOS.

AB - We report the spin Knight shift ([Formula presented]) and the nuclear spin-lattice relaxation rate ([Formula presented]) in the vortex state as a function of magnetic field ([Formula presented]) up to 28 T in the high- [Formula presented] superconductor [Formula presented] ([Formula presented]). At low temperatures well below [Formula presented], both [Formula presented] and [Formula presented] measured around the middle point between the two nearest vortices (saddle point) increase substantially with increasing field, which indicate that the quasiparticle states with an ungapped spectrum are extended outside the vortex cores in a [Formula presented]-wave superconductor. The density of states (DOS) around the saddle point is found to be [Formula presented], with [Formula presented] and [Formula presented] being the normal-state DOS.

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U2 - 10.1103/PhysRevLett.88.077003

DO - 10.1103/PhysRevLett.88.077003

M3 - Article

AN - SCOPUS:77950369865

VL - 88

SP - 4

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 7

ER -