Synthesis and Characterization of a Trigonal Layered Compound AgInS 2 .

Depending on thermal and pressure conditions, AgInS 2 exhibits various crystal structures. In this study, we synthesized a high-purity polycrystalline sample of trigonal AgInS 2 , which is a layered compound, using a high-pressure synthesis technique. The crystal structure was investigated by synchrotron powder X-ray diffraction and the Rietveld refinement. On the basis of band calculation, X-ray photoelectron spectroscopy, and electrical resistance measurements, we found that the obtained trigonal AgInS 2 is a semiconductor. Temperature dependencies of electrical resistance of AgInS 2 were measured by a diamond anvil cell up to 31.2 GPa. Although semiconducting behavior was suppressed with pressure, metallic behavior was not observed within the pressure range investigated in this study.