Structure and transport properties of the first et salt with metal complex anion containing selenocyanate ligand, (ET)/sub 2/TlHg(SeCN)/sub 4/

Summary form only given. Synthesis and structure of the quasi two-dimensional organic salt /spl alpha/-(ET)/sub 2/TlHg(SeCN)/sub 4/ are reported. Distinctions of the bond length distributions in three crystallographically independent ET molecules have been found, which may result in some charge localization in the radical-cation layer. Temperature dependencies of the resistivity in various crystallographic directions have been studied. It has been shown that in the /spl alpha/-(ET)/sub 2/TlHg(SeCN)/sub 4/ salt there is no the low-temperature phase transition into a spin density wave state, characteristic of the /spl alpha/-(ET)/sub 2/TlHg(SeCN)/sub 4/ compounds with M=K, Tl and Rb. The strong Shubnikov-de Haas oscillations have been observed in the magnetic fields up to 36 T and at temperatures down to 0.1 K. Detailed comparison of the structure as well as the electrical and the magnetotrasport properties of this compound to its thiocyanate analog, /spl alpha/-(ET)/sub 2/TlHg(SeCN)/sub 4/ is discussed.