Reproducible inelastic tunneling in Nb/Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[ital x]] point-contact junctions

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.49.1480· OSTI ID:5403867

Gonnelli, R S; Asdente, F ^[1]; Andreone, D ^[2]

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1. Dipartimento di Fisica, Politecnico di Torino, 10129 Torino (Italy)
2. Istituto Elettrotecnico Nazionale Galileo Ferraris, 10125 Torino (Italy)

We discuss the reproducible dependence of tunneling conductance on voltage in Nb/Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[ital x]] (single-crystal) point-contact junctions. The large and symmetric deviations from the background conductance observed at voltages greater than the gap are interpreted in the framework of inelastic electron tunneling at the surface of the high-temperature superconductor. The peaks of the odd second derivative of the tunneling current ([ital d][sup 2][ital I]/[ital dV][sup 2])[sub odd], shifted of the sum of Nb and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[ital x]] energy gaps, show a good correspondence with the peaks of the generalized phonon density of states [ital G]([omega]) determined from neutron-scattering data. The amplitude of the relative deviations of the conductance from the background is explained, as a first approximation, by means of inelastic tunneling at the surface of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[ital x]] assuming a large electron-phonon coupling strength [lambda] for selected phonon modes and, simultaneously, a small potential barrier [ital U] and a small thickness [delta] of the region where the inelastic process occurs.

• OSTI ID: 5403867
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 49:2; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

665412* -- Superconducting Devices-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELEMENTS
HIGH-TC SUPERCONDUCTORS
INELASTIC SCATTERING
JUNCTIONS
METALS
NIOBIUM
OXIDES
OXYGEN COMPOUNDS
SCATTERING
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNNEL EFFECT