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Publication Type: search.filters.UBSTyp.KonferenzbeitragAuthor: search.filters.author.Kahlich, Siegfried

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    Organic metals from chiral BEDT-TTF donors
    (1991) Chen, Ben-ming; Deilacher, Frank; Hoch, Matthias; Keller, Heimo J.; Wu, Pei-ji; Gärtner, Stephan; Kahlich, Siegfried; Schweitzer, Dieter
    We have shown that is is possible to obtain organic metals from chiral molecules. The X-ray results prove an oxidation number of + 1.5 for the radical cations in at least two cases. To our best knowledge. these are: the first examples of BEDT-TTF-related radical cation salts with this oxidation number. As expected, we obtained statistically disordered crystals, containing the two different enantiomers in a "racemic" mixture. The broad smeared-out phase transitions are probably due to this disorder, or may be caused by the three-dimensional interactions which have been observed, so far, only once in a BEDT-TTF radical salt. We will crystallize the metallic compounds using "optically pure" isomers, in the hope to be able to isolate chiral metals.
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    Bulk superconductivity at ambient pressure in polycrystalline pressed samples of organic metals
    (1990) Schweitzer, Dieter; Kahlich, Siegfried; Gärtner, Stephan; Gogu, Emil; Grimm, Hans; Zamboni, Roberto; Keller, Heimo J.
    Bulk superconductivity in polycrystalline pressed samples of αt-(BEDT-TTF)2I3 and βp-(BEDT-TTF)2I3 is reported. This finding shows that organic superconductors can be used in principle for the preparation of electronic devices and superconducting cables.
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    Transport properties of single crystals and polycristalline pressed samples of (BEDT-TTF)2X salts and related coordination polymers
    (1991) Schweitzer, Dieter; Kahlich, Siegfried; Gärtner, Stephan; Gogu, Emil; Grimm, Hans; Heinen, Ilsabe; Klutz, Thomas; Zamboni, Roberto; Keller, Heimo J.; Renner, Gerd
    Ten years ago in 1979, superconductivity was observed for the first time in an organic metal. today, about 30 different organic metals are known, which become superconducting under pressure or ambient pressure. The organic superconductors with the highest transition temperatures are all radical salts of the donor bis(ethylenedithioio)-tettathiafulvalene (BEDT-TTF), namely at ambient pressure (BEDT-TTF)2CU(NCS)2 (Tc = 10.4 K) and αt,-(BEDT-TTF)2I3 (Tc = 8 K) and under isotropic pressure β H- (BEDT-TTF)2I3(0.5 kbar, Tc = 7.5 K) The latter β H-phase can even become superconducting at 8 K and ambient pressure, after a special pressure-temperature cycling procedure i.e. pressurization up to 1 kbar at room temperature, and release of the helium gas pressure at temperarures below 125 K. Nevertheless, this superconducting state at 8 K in β H-(BEDT -TTF)2I3 is only metastable , since warming up the crystal above 125 K and cooling down again under ambient pressure, results only in superconductivity at 1.3 K, the so-called β L - or β-phase.