title: Lattice Dislocations Enhancing Thermoelectric PbTe in Addition to Band Convergence.
abstract: Phonon scattering by nanostructures and point defects has become the primary strategy for minimizing the lattice thermal conductivity (κL) in thermoelectric materials. However, these scatterers are only effective at the extremes of the phonon spectrum. Recently, it has been demonstrated that dislocations are effective at scattering the remaining mid-frequency phonons as well. In this work, by varying the concentration of Na in Pb0.97Eu0.03Te, it has been determined that the dominant microstructural features are point defects, lattice dislocations, and nanostructure interfaces. This study reveals that dense lattice dislocations (≈4 × 1012cm-2) are particularly effective at reducing κL. When the dislocation concentration is maximized, one of the lowest κLvalues reported for PbTe is achieved. Furthermore, due to the band convergence of the alloyed 3% mol. EuTe the electronic performance is enhanced, and a high thermoelectric figure of merit, zT, of ≈2.2 is achieved. This work not only demonstrates the effectiveness of dense lattice dislocations as a means of lowering κL, but also the importance of engineering both thermal and electronic transport simultaneously when designing high-performance thermoelectrics.
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai, 201804, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai, 201804, China.
authors.forename: Zhengzhong
authors.initials: Z
authors.lastname: Jian
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai, 201804, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China.
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China.
authors.forename: Binghui
authors.initials: B
authors.lastname: Ge
authors.affiliation: Northwestern University, Evanston, IL, 60208, USA.
authors.forename: Riley
authors.initials: R
authors.lastname: Hanus
authors.affiliation: Materials Genome Institute, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, 999077, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, SAR, 999077, China.
authors.forename: Mingxin
authors.initials: M
authors.lastname: Huang
authors.affiliation: Northwestern University, Evanston, IL, 60208, USA.
authors.forename: Gerald Jeffrey
authors.initials: GJ
authors.lastname: Snyder
authors.affiliation: Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, School of Materials Science and Engineering, Tongji University, 4800 Caoan Road, Shanghai, 201804, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Pei
keywords: band convergence; lattice dislocations; lattice thermal conductivity; thermoelectrics