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Metal-Insulator Transitions in the Perylene-Dithiolate Family

1985; Volume: 120; Issue: 1 Linguagem: Inglês

10.1080/00268948508075790

0026-8941

Luís Alcácer,

Machine Learning in Materials Science

Abstract In the family of the isostructural perylene-dithio-late organic conductors with general formula (perylene)2M(mnt)2 (mnt=1,2 dicyanoethylene-1,2-dithiol), (M=Pt, Pd, Au), the platinum and palladium compounds undergo clear metal-insulator transitions at 6.5K and 28K respectively and the gold one a broad transition with a minimum in the resistivity at 55 K. In these materials, electrons are itinerant on the segregated perylene stacks and appear to be localized on the dithiolate stacks which are magnetic (one unpaired electron) for M=Pt, Pd and diamagnetic for M=Au. This difference appears to be related to the fact that ID structural fluctuations are observ ed well above the transitions, by X-ray diffuse scattering, in both materials where the dithiolate stack is magnetic, and are not detected in the other. The nature of these transitions will be discussed on the basis of the available data.