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Title: Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene)

Abstract

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.

Authors:
;  [1]; ;  [2]
  1. Department of Physics, University of British Columbia, Vancouver, British Columbia (Canada)
  2. Chemistry and Materials Science Divisions, Argonne National Laboratory, Argonne, Illinois (USA)
Publication Date:
OSTI Identifier:
5170412
DOE Contract Number:  
W-31-109-ENG-38
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter; (United States)
Additional Journal Information:
Journal Volume: 44:10; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 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

Citation Formats

Kornelsen, K, Eldridge, J E, Wang, H H, and Williams, J M. Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene). United States: N. p., 1991. Web. doi:10.1103/PhysRevB.44.5235.
Kornelsen, K, Eldridge, J E, Wang, H H, & Williams, J M. Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene). United States. doi:10.1103/PhysRevB.44.5235.
Kornelsen, K, Eldridge, J E, Wang, H H, and Williams, J M. Sun . "Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene)". United States. doi:10.1103/PhysRevB.44.5235.
@article{osti_5170412,
title = {Infrared optical properties of the 10-K organic superconductor (BEDT-TTF) sub 2 (Cu(NCS) sub 2 ) (where (BEDT-TTF) is bis(ethylenedithio)tetrathiafulvalene)},
author = {Kornelsen, K and Eldridge, J E and Wang, H H and Williams, J M},
abstractNote = {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.},
doi = {10.1103/PhysRevB.44.5235},
journal = {Physical Review, B: Condensed Matter; (United States)},
issn = {0163-1829},
number = ,
volume = 44:10,
place = {United States},
year = {1991},
month = {9}
}