Significant lattice thermal conductivity reduction following phase separation of the highly efficient Ge_xPb_1-xTe thermoelectric alloys

In an attempt to enhance the thermal to electrical conversion efficiency, novel complicated thermoelectric alloys are constantly reported. Most of these reports, correlate the low lattice thermal conductivity values, attributing to the enhanced efficiencies, to nanofeatures apparent in their systems. Yet, since most of the highly efficient thermoelectric materials ever reported are based on complicated alloys, a major reduction of the lattice thermal conductivity can be solely attributed to alloying/disordering effects. The current manuscript, explores by combined experimental and theoretical, using density functional theory and analytical modeling, approaches the lattice thermal conductivity values originated solely by alloying/disordering effects in the highly thermoelectrically efficient p-type Ge_xPb_1-xTe alloys. By comparing these calculated results to various reported experimental values following different synthesis routes, it is shown that solution-treated samples fit well to the calculated values while for phase-separated samples, a significant lattice thermal conductivity reduction of ~50% might be expected.