Conductance spectroscopy of high- T c single-grain-boundary junctions in the YBa 2</mml:…
1993; American Physical Society; Volume: 48; Issue: 2 Linguagem: Inglês
10.1103/physrevb.48.1175
ISSN1095-3795
AutoresP. Chaudhari, E. Sarnelli, J. R. Kirtley, J. A. Lacey,
Tópico(s)Advanced Condensed Matter Physics
ResumoWe have measured the conductance spectra of ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ thin-film grain-boundary junctions. For voltages between 2 and 12 meV there are two sets of sharp structures. One appears at nearly regular multiples of 2.4 mV, out to 9.5 mV; the conductance peak at 9.5 mV is split in a magnetic field parallel to the film ab planes. A second set of peaks with spacing 0.1--0.2 mV extends from low voltages to V\ensuremath{\sim}11.5 mV; these peaks are insensitive to magnetic fields but merge into the background noise at about 50 K. At higher voltages (V>12 mV) peaks at roughly the phonon energies appear. We speculate on the origins of these features.
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