title: Role of sodium doping in lead chalcogenide thermoelectrics.
abstract: The solubility of sodium and its effects on phonon scattering in lead chalcogenide PbQ (Q = Te, Se, S) family of thermoelectric materials was investigated by means of transmission electron microscopy and density functional calculations. Among these three systems, Na has the highest solubility limit (~2 mol %) in PbS and the lowest ~0.5 mol %) in PbTe. First-principles electronic structure calculations support the observations, indicating that Na defects have the lowest formation energy in PbS and the highest in PbTe. It was also found that in addition to providing charge carriers (holes) for PbQ, Na introduces point defects (solid solution formation) and nanoscale precipitates; both reduce the lattice thermal conductivity by scattering heat-carrying phonons. These results explain the recent reports of high thermoelectric performance in p-type PbQ materials and may lead to further advances in this class of materials.
authors: Frontier Institute of Science and Technology (FIST), Xi'an Jiaotong University, Xi'an 710054, PR China. he.jq@sustc.edu.cn
authors: Jiaqing
authors: J
authors: He
authors: Li-Dong
authors: LD
authors: Zhao
authors: Jin-Cheng
authors: JC
authors: Zheng
authors: Jeff W
authors: JW
authors: Doak
authors: Haijun
authors: H
authors: Wu
authors: Hui-Qiong
authors: HQ
authors: Wang
authors: Yeseul
authors: Y
authors: Lee
authors: Chris
authors: C
authors: Wolverton
authors: Mercouri G
authors: MG
authors: Kanatzidis
authors: Vinayak P
authors: VP
authors: Dravid