Possible pseudogap behavior of electron-doped high-temperature superconductors - art. no. 100507

Citation
S. Kleefisch et al., Possible pseudogap behavior of electron-doped high-temperature superconductors - art. no. 100507, PHYS REV B, 6310(10), 2001, pp. 0507
Citations number
28
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B
ISSN journal
01631829 → ACNP
Volume
6310
Issue
10
Year of publication
2001
Database
ISI
SICI code
0163-1829(20010301)6310:10<0507:PPBOEH>2.0.ZU;2-D
Abstract
We have measured the low-energy quasiparticle excitation spectrum of the el ectron doped high-temperature superconductors (HTS) Nd1.85Ce0.15CuO4-y and Pr1.85Ce0.15CuO4-y as a function of temperature and applied magnetic field using tunneling spectroscopy. At zero magnetic field, for these optimum dop ed samples no excitation gap is observed in the tunneling spectra above the transition temperature T-c. In contrast, below T-c for applied magnetic fi elds well above the resistively determined upper critical field, a clear ex citation gap at the Fermi level is found which is comparable to the superco nducting energy gap below T-c. Possible interpretations of this observation are the existence of a normal-state pseudogap in the electron doped HTS or the existence of a spatially nonuniform superconducting state.