2 research outputs found
Resonant States in the Electronic Structure of the High Performance Thermoelectrics AgPb_{2+m}$ ; The Role of Ag-Sb Microstructures
Ab initio electronic structure calculations based on gradient corrected
density functional theory were performed on a class of novel quaternary
compounds AgPb_{2+m}$, which were found to be excellent high
temperature thermoelctrics with large figure of merit ZT ~2.2 at 800K. We find
that resonant states appear near the top of the valence and bottom of the
conduction bands of bulk PbTe when Ag and Sb replace Pb. These states can be
understood in terms of modified Te-Ag(Sb) bonds. Electronic structure near the
gap depends sensitively on the microstructural arrangements of Ag-Sb atoms,
suggesting that large ZT values may originate from the nature of these ordering
arrangements.Comment: Accepted in Physical Review Letter