Peculiarities of the Electronic Properties of the κ-Phase Structures (BEDT-TTF)2Cu(N(CN)2)X with X=Cl, Br, I |
| K. Andres, H. Posselt, N.D. Kushch, M. Kund, W. Biberacher Walther-Meissner-Institut for Low Temperature Research, D-85748 Garching, Germany and G. Saito Faculty of Chemistry, Kyoto University, Kyoto, Japan |
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| The structure of the title compounds is similar to other κ-phase structures with respect to the checkerboard-like arrangement of the ET dimers (ET = BEDT-TTF) in the conducting planes, but different by the tilt alternation of these dimers in successive planes. The resulting inequivalence of these planes tends to destabilize the metallic state which becomes extremely sensitive to changes in the S-S overlaps of neighbouring ET molecules. Such changes may result from anion substitution, lattice expansion, or also from ordering effects of the ethylene end groups of the ET molecules. They lead to quite different electronic properties of the three isostructural compounds. We focus especially on the strongly pressure-dependent properties of the Cl-compound, where a coexistence of magnetically ordered and superconducting states with rather spectacular superconducting reentrance effects is observed. |
| DOI: 10.12693/APhysPolA.87.761 PACS numbers: 72.80.Le, 74.70.Kn, 75.50.Ee, 75.50.Gg |