Electrical conductivity and X-ray diffuse scattering study of the family of organic conductors (perylene)2M(mnt)2, (M=Pt, Pd, Au)

Abstract

Reports resistivity measurements along the high-conductivity axis of Per2Pt(mnt)2, Per2Pd(mnt)2 and Per2-Au(mnt)2. At low temperatures a clear metal-insulator phase transition is observed at 6.5K and 28K, respectively for the first two salts, while it appears very gradually for the Au salt. The X-ray study shows above these critical temperatures one-dimensional structural fluctuations for Per2Pt(mnt)2 and Per2Pd(mnt)2, which are attributed to the M(mnt)2 stacks, and no such scattering for Per2Au(mnt)2, down to 12K. The diffuse scattering 'condenses' in superstructure reflections below 28K in Per2Pd(mnt)2, which thus might undergo a spin-Peierls phase transition. The nature of these various phase transitions is discussed.