Physical Review Letters 106 206601 (2011)
The structure-property relation is a key outstanding problem in the study of nanocomposite mate- rials. Here we elucidate the fundamental physics of nanodopants in thermoelectric nanocomposites XPbmYTe2+m (X=Ag,Na; Y=Sb,Bi). First-principles calculations unveil a sizable band-gap widen- ing driven by nanodopant-induced lattice strain and a band split-off mainly caused by the spin-orbit interaction in nanodopant. Boltzmann transport calculations on PbTe with modified band mimick- ing nanodopant-induced modulations show significant but competing effects on high-temperature electron transport behavior. These results offer insights for understanding experimental findings and optimizing thermoelectric properties of narrow band-gap semiconductor nanocomposites.
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