Please use this identifier to cite or link to this item: http://dx.doi.org/10.18419/opus-7633
Keller, Heimo J.
|Title:||Resonance Raman investigations of the symmetric stretching mode of I3- anions in α and β phases of di-bis(ethylenedithio)tetrathiafulvalene tri-iodide|
|metadata.ubs.publikation.source:||Physical review, B 36 (1987), S. 6881-6888. URL http://dx.doi.org./10.1103/PhysRevB.36.6881|
|Abstract:||The resonance Raman spectra of I3- anions in the organic superconductor β-(BEDT-TTF)2I3 [BEDT-TTF represents bis(ethylenedithio)tetrathiafulvalene] were studied and discussed in comparison with the nonsuperconducting phase of α-(BEDT-TTF)2I3. In both modifications at low temperature a splitting of the Raman mode assigned to the symmetric stretching mode of the I3- anions was discovered. The splitting of this mode in the β-(BEDT-TTF)2I3 crystals is related to the commensurate superstructure developed below 125 K in contradiction to the α phase where the splitting is related to a crystal-field effect. It is shown that an electronic excitation of the β-phase crystals by laser light can induce a structural transformation at least in a thin layer of the surface. This transformation is observed by a disappearance of the splitting of the symmetric stretching mode. The structural change can be related to a transformation from the commensurate superstructure with a superconducting transition temperature Tc=1.3 K into a more ordered and symmetric structure which becomes superconducting at Tc=8.1 K.|
|Appears in Collections:||15 Fakultätsübergreifend / Sonstige Einrichtung|
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