Natural nanostructure and superlattice nanodomains in AgSbTe2

AgSbTe2 has long been of interest for thermoelectric applications because of its favorable electronic properties and its low lattice thermal conductivity of similar to 0.7W/mK. In this work, we report new findings from a high-resolution transmission electron microscopy study revealing two nanostructures in single crystal Ag1-xSb1+xSb2+x (with x = 0, 0.1, 0.2); (i) a rippled natural nanostructure with a period of similar to 2.5-5nm and (ii) superlattice ordered nanodomains consistent with cation ordering predicted in previous density functional theory studies. These nanostructures, combined with point-defects, probably serve as sources of scattering for phonons, thereby yielding a low lattice thermal conductivity over a wide temperature range. (C) 2014 AIP Publishing LLC.