Phase Transition in SnTe with Low Carrier Concentration

Abstract

The phase transition in SnTe was investigated on a single crystal with low carrier concentration (0.88×10²⁰ cm⁻³) by the neutron diffraction method. A second-order phase transition takes place at 98 K. Comparison of this considerably high transition temperature with previous data has revealed that the phase transition is strongly dependent on the carrier concentration and that the above temperature may be taken as an almost carrier-free limit. Possible origins of this dependence are speculated. Temperature change of the relative displacement of two sublattices in the rhombohedral phase was derived. At 25 K the single atom-position parameter deviates by 0.0040 from the value, 0.25, in the cubic phase. In the pseudobinary Pb_1−xSn_xTe system no evidence of phase transition was found for tin content x up to 0.35 at temperatures higher than 5 K even with low carrier concentration samples.