Synthesis of Molecular Dodecanuclear Carbon-centered Rhenium Cluster Re12CS17 and its Conducting Properties

The unique dodecanuclear cluster compound Re12CS17 was prepared and studied by X-ray, complex impedance method and density functional theory (DFT). The compound is amorphous, possesses semiconducting properties. Computer simulations showed that the Re and S atoms at the external borders of the neighboring molecules Re12CS17 can form sufficiently strong Re•••S intermolecular bonds, similar to the Mo•••S intermolecular bonds of cuboctahedron Mo6S8 molecules in the Chevrel phases. (doi: 10.5562/cca1973

Electronic properties and phase transitions in low-dimensional semiconductors

We present the first review of the current state of the literature on electronic properties and phase transitions in TlX and TlMX2 (M = Ga, In; X = Se, S, Te) compounds. These chalcogenides belong to a family of the low-dimensional semiconductors possessing chain or layered structure. They are of significant interest because of their highly anisotropic properties, semi- and photoconductivity, non-linear effects in their I-V characteristics (including a region of negative differential resistance), switching and memory effects, second harmonic optical generation, relaxor behavior and potential applications for optoelectronic devices. We review the crystal structure of TlX and TlMX2 compounds, their transport properties under ambient conditions, experimental and theoretical studies of the electronic structure, transport properties and semiconductor-metal phase transitions under high pressure, and sequences of temperature-induced structural phase transitions with intermediate incommensurate states. Electronic nature of the ferroelectric phase transitions in the above-mentioned compounds, as well as relaxor behavior, nanodomains and possible occurrence of quantum dots in doped and irradiated crystals is discussed.Comment: 70 pages, 38 figure