Electron-phonon interactions in the superconducting Chevrel phase compounds Mo sub 6 Se sub 8 minus x S sub x

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.4344· OSTI ID:5422759

Furuyama, M; Kobayashi, N; Muto, Y ^[1]

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1. Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980, Japan (JP)

The specific heat of nine single crystals of the Chevrel phase compounds Mo{sub 6}Se{sub 8{minus}{ital x}}S{sub {ital x}} (0{le}{ital x}{lt}=4.0) has been investigated in the temperature range 1.5--9.0 K in magnetic fields of 0 and 6 T. Using the BCS theory with strong-coupling corrections, the thermodynamic properties and information on the electron-phonon interactions have been obtained. The superconducting transition temperatures {ital T}{sub {ital c}} of these compounds decrease with increasing S concentration {ital x}, and the electron-phonon interactions of this system change from strong to weak. In spite of the change in {ital T}{sub {ital c}}, the bare electronic density of states is nearly constant for all samples. The value of {ital T}{sub {ital c}} depends on the average phonon frequency through the electron-phonon coupling constant. The anomalous lattice specific heat has been observed for low concentration samples. This is explained by assuming low-lying soft-phonon modes, which were reported by inelastic neutron experiments for Mo{sub 6}Se{sub 8}, in addition to a molecular crystal model. The relationship between the electron-phonon interactions and the low-lying soft-phonon modes is discussed.

• OSTI ID: 5422759
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:7; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BCS THEORY
CHALCOGENIDES
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON-PHONON COUPLING
ENERGY-LEVEL DENSITY
MAGNETIC FIELDS
MATHEMATICAL MODELS
MOLYBDENUM COMPOUNDS
MOLYBDENUM SELENIDES
MOLYBDENUM SULFIDES
MONOCRYSTALS
PARTICLE MODELS
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
SELENIDES
SELENIUM COMPOUNDS
SPECIFIC HEAT
STRONG-COUPLING MODEL
SULFIDES
SULFUR COMPOUNDS
SUPERCONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE