Far-infrared studies of superconducting V/sub 3/Si, Nb/sub 3/Ge, and Nb

Technical Report · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6063000

Perkowitz, S

A strong effort has continued in understanding the behavior of the electron-phonon spectral function ..cap alpha../sup 2//sub tr/F(..omega..) as measured in V/sub 3/Si by far-infrared methods. Our result implied two features in ..cap alpha../sup 2//sub tr/F(..omega..) that differed from the neutron scattering results: the existence of a new low energy peak at about 6 MeV and a shift down of the intermediate energy peak from 25 to 18 MeV. Recent work by Mitrovic and Carbotte shows that these increased low energy weights are not needed to explain thermodynamic results for V/sub 3/Si, yet the far infrared structure which leads to them is quite clear. The apparent resolution of the anomaly may lie in a very recent refinement by Mitrovic of Allen's original theory. The original work assumed a constant electronic density of states but the new version allows this quantity to vary near the Fermi energy. Calculations are now under way to determine whether this factor can explain the observed far infrared data without recourse to additional structure in ..cap alpha../sup 2//sub tr/F(..omega..) itself. If so, Mitrovic's theory will provide the best available model for further analysis in Nb and Nb/sub 3/Ge as well as in V/sub 3/Si. A second effort has been to better understand the connection between strong coupling theory and BCS theory as modified by the introduction of a finite scattering time tau. The latter approach has worked very well in fitting our far infrared data in V/sub 3/Si/sup 7/ and homogeneous NbN/sup 8/ despite the strong coupled nature of both materials.

• Research Organization: Emory Univ., Atlanta, GA (USA). Dept. of Physics
• DOE Contract Number: AS05-79ER10436
• OSTI ID: 6063000
• Report Number(s): DOE/ER/10436-4; ON: DE83012786
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
BCS THEORY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ELECTRON-PHONON COUPLING
ELEMENTS
FAR INFRARED RADIATION
FILMS
FUNCTIONS
GERMANIUM COMPOUNDS
INFRARED RADIATION
METALS
NIOBIUM
NIOBIUM COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SILICIDES
SILICON COMPOUNDS
SPECTRAL FUNCTIONS
SUPERCONDUCTING FILMS
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRANSMISSION
VANADIUM COMPOUNDS
VANADIUM SILICIDES