Density of states and isotope effect in BiO superconductors: Evidence for nonphonon mechanism

Journal Article · Mon Oct 03 04:00:00 EDT 1988 · Phys. Rev. Lett.; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.61.1670· OSTI ID:6781765

Batlogg, B; Cava, R J; Rupp, Jr, L W; Mujsce, A M; Krajewski, J J; Remeika, J P; Peck, Jr, W F; Cooper, A S; Espinosa, G P

We report measurements of the physical properties of the 30-K superconductor Ba/sub 0.6/K/sub 0.4/BiO/sub 3/, including upper and lower critical fields and normal-state susceptibility. From the results and from comparison with BaPb/sub 0.75/Bi/sub 0.25/O/sub 3/ and band-structure calculations it is concluded that the BiO superconductors are in the weak-coupling limit, implying that the anomalously high T/sub c/'s are not due to conventional, strong electron-phonon coupling. A sizable oxygen isotope effect of very similar magnitude is found for both compounds (..cap alpha.. = 0.2--0.25). We speculate that ''phononic'' effects in these materials are actually only indicative of dressed electronic excitations mediating superconducting pairing.

• Research Organization: ATandT Bell Laboratories, Murray Hill, New Jersey 07974
• OSTI ID: 6781765
• Journal Information: Phys. Rev. Lett.; (United States), Journal Name: Phys. Rev. Lett.; (United States) Vol. 61:14; ISSN PRLTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CHALCOGENIDES
COUPLING
CRITICAL FIELD
ENERGY-LEVEL DENSITY
EVEN-EVEN NUCLEI
ISOTOPES
ISOTOPIC EXCHANGE
LEAD COMPOUNDS
LIGHT NUCLEI
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
NUCLEI
OXIDES
OXYGEN 16
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
STABLE ISOTOPES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
VERY LOW TEMPERATURE