Conduction processes in the layered semiconductor compoundFePS3

Abstract
We have measured, as a function of temperature, the thermopower, the dc conductivity, and photoconductivity of FePS3 single crystals. For temperatures below 430 K the thermopower shows an activated behavior, whereas at higher temperatures it is almost temperature independent. The dc dark conductivity and photoconductivity are thermally activated over the entire investigated temperature range. Moreover, ac-conductivity measurements have been carried out as a function of both temperature and frequency from 400 Hz to 100 kHz in the 340–500-K temperature region. The transport mechanisms involved in different temperature ranges have been identified. The results have been interpreted on the basis of a simplified energy-band scheme.