Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene)
- Department of Physics, University of British Columbia, Vancouver, British Columbia (Canada)
- Chemistry and Materials Science Divisions, Argonne National Laboratory, Argonne, Illinois (USA)
Low-temperature polarized bolometric absorption measurements have been performed on the {ital T}{sub {ital c}}=10.4 K organic superconductor {kappa}-(BEDT-TTF){sub 2}(Cu(NCS){sub 2}), where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene. The ratio of the absorption at 5.3 K to that at 10.5 K from 10 to 40 cm{sup {minus}1} showed no evidence of a conventional BCS gap. Polarized-reflectivity measurements at temperatures between 10 and 295 K are also reported for both the protonated and deuterated compounds, between 200 and 8000 cm{sup {minus}1}. The 10-K spectra were calibrated by a technique of simultaneously measuring the reflectivity {ital R} and the absorptance, 1{minus}{ital R}. The resulting conductivities display vibrational features superimposed on an electronic background. This background shifts from mid-infrared interband transitions, when the dc conductivity is low, to far-infrared intraband transitions as the dc conductivity increases. The vibrations have been assigned to a mixture of normally inactive {ital a}{sub {ital g}} modes and normally active {ital b}{sub 2{ital u}} modes of the BEDT-TTF molecule. A few of both types couple strongly to the charge carriers. One in particular has a very temperature-dependent frequency due to the changing intensity of the mid-infrared band.
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 5170412
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 44:10; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BEDT-TTF
INFRARED SPECTRA
COPPER COMPLEXES
CYANOGEN
ORGANIC SULFUR COMPOUNDS
ORGANIC SUPERCONDUCTORS
ABSORPTION SPECTRA
BOLOMETERS
BROMINE COMPOUNDS
ENERGY GAP
POLARIZATION
REFLECTIVITY
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE
COMPLEXES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
SPECTRA
SUPERCONDUCTORS
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES
360603* - Materials- Properties