Silver transfer in proustite Ag3AsS3 at high temperatures: Conductivity and single-crystal X-ray studies

Single crystals of proustite Ag3AsS3 have been characterised by impedance spectroscopy and single-crystal X-ray diffraction in the temperature ranges of 295-543 and 295-695 K, respectively. An analysis of the one-particle potential of silver atoms shows that in the whole measuring temperature range defects in the silver substructure play a major role in the conduction mechanism. Furthermore, the silver transfer is equally probable within silver chains and spirals, as well as between chains and spirals. The trigonal R3c room temperature phase does not change until the decomposition of the crystal. The electric anomaly of the first-order character which appears near 502 K is related to an increase in the electronic component of the total conductivity resulting from Ag2S deposition at the sample surface. - Joint probability density function map of silver atoms at T=695 K