The goal of this work is to characterize the structure and lattice dynamics of complex
chalcogenide alloys. Particular interest is paid to the system AgPbmSbTem+2
(LAST-m), AgSbTe2 and the binaries PbTe, SnTe and GeTe. Synchrotron radiation
studies including high energy X-ray diraction and nuclear inelastic scattering,
and macroscopic measurements of heat capacity and elastic constants were
performed. A new resonant ultrasound spectroscopy setup with capable of performing
measurements from room temperature to 1073K was built for mechanical
characterization of the thermoelectric alloys at their working temperatures.