Spectroscopic and transport properties of a new low-dimensional single crystal

Abstract

Spectroscopic properties (IR, EPR & Optical absorption), DC electrical conductivity (77K-300K range) of SrCu(HCOO)4 single crystal have been studied. The IR spectrum gives five strong bands at 3250, 1608, 1331, 779 and 667 cm−1. These bands are attributed to the stretching and bending vibrations of formate ion atoms. EPR results indicate that the Jahn-Teller active copper(II) ion is present in tetragonal elongated octahedral crystal field. Optical absorption in UV, Visible and in near Infrared regions shows ten absorption bands. The absorption bands in the UV and Visible regions are attributed to the charge transfer and cubic field splitting respectively. The eight absorption bands in the near infrared region are assigned to the d-d transitions of copper(II) ion, the Hubbard energy gaps of the crystal and to the Fermi energy gap of the crystal. Finally the weak absorptions are attributed to the linear combinations of IR bands, DC electrical conductivity of this crystal is assigned to the hopping mechanism of holes. The peierls transition is observed at about 220K.