beta. -(ET)/sub 2/X organic superconductors: linear-anion control of structure and ambient-pressure superconductivity, and the first point-contact tunneling studies of. beta. -(ET)/sub 2/AuI/sub 2/ implying extremely strong coupling
Three ambient-pressure organic superconductors have been reported for linear-anion-containing 20 metallic ..beta..-(ET)/sub 2/X systems: X = I/sub 3//sup -/ (T/sub c/'s approx. = 1.5 K and 8 K under > 0.6 kbar pressure), IBr/sub 2//sup -/ (T/sub c/ approx. = 2.8 K), and AuI/sub 2//sup -/ (T/sub c/ approx. = 5 K). These systems form the basis for structure-property correlations because the T/sub c/'s scale with unit cell volume, which increases with increasing anion length. When the linear anion length becomes approximately 14 to 20% shorter than that of the longest member, I/sub 3//sup -/, as is the case for ICI/sub 2//sup -/ and AuCl/sub 2//sup -/, the electrical properties become those of a 1D metallic system in which spin-density-wave insulating ground states dominate at low temperature. In the case of the highest ambient-pressure T/sub c/ material, X = AuI/sub 2//sup -/, we report the first unambiguous point-contact tunneling measurements of the superconducting energy gap, ..delta.., which reveals a BCS temperature dependence but with a gap 5 times larger than the weak-coupling value, implying extremely strong coupling. 13 refs., 7 figs.
- Research Organization:
- Argonne National Lab., IL (USA); Sandia National Labs., Albuquerque, NM (USA); North Carolina State Univ., Raleigh (USA). Dept. of Chemistry
- DOE Contract Number:
- AC04-76DP00789; W-31-109-ENG-38
- OSTI ID:
- 5282324
- Report Number(s):
- CONF-8605146-6; ON: DE86014597
- Resource Relation:
- Conference: 15. Yamada conference on physics and chemistry of quasi one-dimensional conductors, Lake Kawaguchi, Japan, 26 May 1986; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BEDT-TTF
ELECTRIC CONDUCTIVITY
STRUCTURE-ACTIVITY RELATIONSHIPS
SUPERCONDUCTORS
BAND THEORY
ELECTRONIC STRUCTURE
MOLECULAR STRUCTURE
TRANSITION TEMPERATURE
TUNNEL EFFECT
ELECTRICAL PROPERTIES
HETEROCYCLIC COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHYSICAL PROPERTIES
THERMODYNAMIC PROPERTIES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)