Charge‐Compensated Compound Defects in Ga‐containing Thermoelectric Skutterudites

• DOI: 10.1002/adfm.201202571
• Publication Date: 2013-02-06T14:41:01Z
• Authors: Yuting Qiu; Lili Xi; Xun Shi; Pengfei Qiu; Wenqing Zhang; Lidong Chen; James R. Salvador; Jung Y. Cho; Jihui Yang; Yuan‐chun Chien; Sinn‐wen Chen; Yinglu Tang; G. Jeffrey Snyder
• Keywords: Skutterudite; Charge carrier; Phonon scattering

Abstract Heavy doping changes an intrinsic semiconductor into a metallic conductor by the introduction of impurity states. However, Ga impurities in thermoelectric skutterudite CoSb 3 with lattice voids provides example to contrary. Because dual‐site occupancy single charge‐compensated compound defects are formed. By combining first‐principle calculations and experiments, we show that atoms occupy both void Sb sites couple each other. The donated electrons from void‐filling (Ga VF ) saturate dangling bonds Sb‐substitutional ). stabilization as defect extends region phase stability toward 0.15 Co 4 11.95 whereas solid–solution other directions ternary diagram is much smaller. A proposed for Ga‐Co‐Sb given. This compensated complex leads nearly heavy reduced thermal conductivity ( κ L which can also be attributed effective scattering low‐ high‐frequency phonons occupant impurities. Such system maintains low carrier concentration therefore high thermopower, figure merit quickly increases 0.7 at content 0.1 per 12 concentrations on order 10 19 cm −3 .