EFFECT OF PRESSURE ON RESISTIVITY AND MOSSBAUER-SPECTRA OF THE MIXED-VALENCE COMPOUND SN2S3

A continuous decrease of the resistivity by five orders of magnitude has been observed on Sn2S3 at room temperature under pressures up to 120 kbar. PbSnS3 shows only a decrease by three orders of magnitude. SnGeS3 and PbGeS3 remain insulators in the same pressure range. Mössbauer measurements on 119Sn in Sn 2S3 at room temperature and pressures up to 55 kbar indicate that Sn2S3 remains a type I mixed valence compound in this pressure range. The two crystallographic positions of Sn exhibit significantly different Debye temperatures, ΘD(Sn II)=207 K, ΘD(SnIV)=429 K. Moreover, distinct 119Sn pressure shifts ∂δ(SnII)/ ∂P≈+2.1 mm/sec kbar and ∂δ(SnIV)/∂p≈+1.2 mm/sec kbar are observed. © 1979 American Institute of Physics.