Impurity and fluctuation effects in charge-density-wave superconductors

Journal Article · Thu Apr 01 00:00:00 EST 1982 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.25.4562· OSTI ID:6826921

Grest, G S; Levin, K; Nass, M J

We formulate a theory of a charge-density-wave (CDW) distorted superconductor, in the presence of impurities and CDW fluctuations. This theory is expected to be applicable to the layered compound 2H-NbSe/sub 2/. Our primary aim is to compute the superconducting density of states N/sub s/(..omega..). We also obtain the temperature dependence of the order parameter ..delta... We show, when all other parameters are fixed, that nonmagnetic impurites will raise the superconducting transition temperature and ..delta... Since the CDW gap W/sub q/ is expected to decrease with concentration, this effect should be even more pronounced. For nonmagnetic impurities, N/sub s/(..omega..) is found to be ''BCS-like'' with a gap at ..delta..not =..delta../sup BCS/, with subsidiary structure at ..omega.. = (..delta../sup 2/+W/sup 2//sub Q/). As the nonmagnetic impurity concentration is further increased this structure rounds out and N/sub s/(..omega..) approaches the strict BCS limit. CDW fluctuation effects are expected to lead to fine structure in N/sub s/(..omega..) at the characteristic phonon frequency. In principle, an analysis of (future) tunneling data will give detailed information about the CDW excitations, some of which has been obtained from Raman spectroscopy.

• Research Organization: The Department of Physics, Purdue University, West Lafayette, Indiana 47907
• OSTI ID: 6826921
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Vol. 25:7
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
SUPERCONDUCTORS
IMPURITIES
PLASMA WAVES
ENERGY-LEVEL DENSITY
FLUCTUATIONS
LAYERS
NIOBIUM SELENIDES
ORDER PARAMETERS
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
TUNNEL EFFECT
CHALCOGENIDES
NIOBIUM COMPOUNDS
PHYSICAL PROPERTIES
SELENIDES
SELENIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VARIATIONS
656101* - Solid State Physics- Superconductivity- General Theory- (-1987)