The average and local structures of the (PbTe) 1-x (PbS) x system of thermoelectric materials has been studied using the Rietveld and atomic pair distribution function methods. Samples with 0.25≤x are macroscopically phase separated. Phase separation was suppressed in a quenched x=0.5 sample which, nonetheless, exhibited a partial spinodal decomposition. The promising thermoelectric material with x=0.16 showed intermediate behavior. Combining TEM and bulk scattering data suggests that the sample is a mixture of PbTe-rich material and a partially spinodally decomposed phase similar to the quenched 50% sample. This confirms that, in the bulk, this sample is inhomogeneous on a nanometer length scale, which may account for its enhanced thermoelectric figure of merit.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Aug 6 2009|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics