Microwave conductivity of metal complexes TTF[M(dmit)2]2 (M=Pd, Ni)

Abstract

The highly conducting TTF [M(dmit)2]2 compounds with M= Pd, Ni have been investigated at microwaves. The temperature dependence of real and imaginary part of conductivity was measured from T=77K to 300 K. The Ni salt remains metallic, while the Pd salt reveals at f=2GHz a metal-insulator transition at Tp=260K with the negative dielectric constant below Tp. The non-linear microwave conductivity of Pd salt was observed in the temperature range 105÷200K, while the Ni salt exhibited the linear conductivity. The results observed can not be accounted for in the framework of known model approach of the collective CDW transport.