Inter-Atomic Force Constants From Correlation Effects Among Thermal Displacement Of Atoms In Pbte

Diffuse neutron scattering measurements have been performed on powder PbTe at 10 and 294 K using high resolution powder diffractometer installed at JRR-3 in Japan Atomic Energy Agency. Oscillatory diffuse scattering intensity is clearly observed at 294 K. The observed diffuse scattering intensities are analysed by including correlation effects among thermal displacements of atoms in the function describing background in refinement analysis. The force constants between the first and second nearest neighbouring atoms in PbTe are obtained from the values of correlation effects and Debye-Waller temperature parameters.