Crystal structure, electronic and transport properties of AgSbSe 2 and AgSbTe 2

Abstract

Undoped and p- and n -doped AgSbX 2 (X=Se and Te) materials were synthesized by direct fusion technique. The structural properties were investigated by X-ray diffraction and SEM microscopy. The electrical conductivity, thermal conductivity and Seebeck coefficient have been measured as a function of temperature in the range from 300 to 600 K. To enlighten electron transport behaviours observed in AgSbSe 2 and AgSbTe 2 compounds, electronic structure calculations have been performed by the Korringa–Kohn–Rostoker method as well as KKR with coherent potential approximation (KKR-CPA) for ordered (hypothetical AgX and SbX as well as AgSbX 2 approximates) and disordered systems (Ag 1− x Sb x X), respectively. The calculated density of states in the considered structural cases shows apparent tendencies to opening the energy gap near the Fermi level for the stoichiometric AgSbX 2 compositions, but a small overlap between valence and conduction bands is still present. Such electronic structure behaviour well agrees with the semimetallic properties of the analyzed samples.