High-pressure X-ray diffraction study of ternary and non-stoichiometric PbTe and PbSe crystals

The paper reports the pressure‐induced phase transitions observed in ternary PbTe and PbSe compounds (Pb1–x Snx Te, Pb1–x Mnx Te, Pb1–x Snx Se) and non‐stoichiometric PbTe ones (Pb0.55Te0.45, Pb0.45Te0.55) at room temperature in the range of 0 to14 GPa by means of angle‐dispersive X‐ray diffraction (ADXRD). The structure of the intermediate high‐pressure phase appearing above ∼6 GPa for all PbTe‐based compounds was established to be Pnma (orthorhombic), like in binary PbTe. The patterns of the intermediate high‐pressure phase of Pb1–x Snx Se (x = 0.125) were found to correspond entirely neither to GeS nor to orthorhombic Pnma, but the calculated reflections for GeS type were closer to the experimental ones. A model of the phase transformations is discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)