Point-contact tunneling study of the high-transition-temperature-superconductor Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8
The point-contact (Pt-Ir probe) tunneling measurements on high-T{degree}c superconducting Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals ({Tc} = 82 K) have been performed at low temperatures of 4.2 K to 77 K. A high-conductance region around the origin, which is attributed to the junction of the pure-metallic-bridge type of point-contact tunneling, was observed. There are also several current steps beyond the high-conductance region in the I-V curves, corresponding to conductance troughs, which are either zero or negative, in the dI/dV characteristics in the tunneling spectra. These are pronounced structures indicative of bound states in tunneling spectroscopy. a superconducting energy gap of {Delta} = 28 {plus minus} 2 meV was identified from tunneling spectra taken at 4.2 K and as a function of temperature. Current jumps and drops with some regularity in voltage intervals between jumps occur at high applied voltage (> 100 mV). This resonance tunneling is the result of the effects of quantization due to the layered-structure of the crystal. A model based on the superlattice-like nature of the crystal was developed to interpret the tunneling observation of the bound states and the energy gap.
- Research Organization:
- Drexel Univ., Philadelphia, PA (United States)
- OSTI ID:
- 7110709
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ENERGY GAP
HIGH-TC SUPERCONDUCTORS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TUNNEL EFFECT