Effect of nonmagnetic impurities on the Raman spectra of the superconductor niobium diselenide

Journal Article · Wed Apr 01 04:00:00 EST 1981 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.23.3222· OSTI ID:6583686

Sooryakumar, R; Klein, M V; Frindt, R F

We recently published the results of observation of the superconducting energy gap in 2H-NbSe/sub 2/ by Raman scattering. The gap is observed by the appearance of two new Raman-active modes of different symmetries A (18 cm/sup -1/) and E (15 cm/sup -1/) when the sample is immersed in superfluid helium. Theoretical calculations by C. A. Balseiro and L. M. Falicov show that these gap excitations gain their Raman activity by coupling to low-lying phonons. Crystal growth techniques, which produce nonmagnetic impurities, are known to have a small effect on superconductivity while tending to inhibit the formation of charge-density waves (CDW) in 2H-NbSe/sub 2/. By studying such diverse samples, we present data to show the necessity of the CDW state to observe the superconducting gap excitation. The role of impurities in suppressing CDW formation is also revealed from the data.

• Research Organization: Material Research Laboratory and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
• OSTI ID: 6583686
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 23:7; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
656102 -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHALCOGENIDES
CHARGE DENSITY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY GAP
ENERGY-LEVEL TRANSITIONS
EXCITATION
IMPURITIES
NIOBIUM COMPOUNDS
NIOBIUM SELENIDES
PHYSICAL PROPERTIES
RAMAN SPECTRA
SELENIDES
SELENIUM COMPOUNDS
SPECTRA
SUPERCONDUCTIVITY
TRANSITION ELEMENT COMPOUNDS