期刊
APPLIED PHYSICS LETTERS
卷 112, 期 18, 页码 -出版社
AMER INST PHYSICS
DOI: 10.1063/1.5002587
关键词
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资金
- Midwest Integrated Center for Computational Materials (MICCoM) - U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division [5J-30161-0010A]
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-06CH11357]
- Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]
PbTe, one of the most promising thermoelectric materials, has recently demonstrated a thermoelectric figure of merit (ZT) of above 2.0 when alloyed with group II elements. The improvements are due mainly to significant reduction of lattice thermal conductivity (kappa(l)), which was in turn attributed to nanoparticle precipitates. However, a fundamental understanding of various phonon scattering mechanisms within the bulk alloy is still lacking. In this work, we apply the newly-developed density-functional-theory-based compressive sensing lattice dynamics approach to model lattice heat transport in PbTe, MTe, and Pb-0.94 M0.06Te (M = Mg, Ca, Sr, and Ba) and compare our results with experimental measurements, with focus on the strain effect and mass disorder scattering. We find that (1) CaTe, SrTe, and BaTe in the rock-salt structure exhibit much higher kappa(l) than PbTe, while MgTe in the same structure shows anomalously low kappa(l); (2) lattice heat transport of PbTe is extremely sensitive to static strain induced by alloying atoms in solid solution form; (3) mass disorder scattering plays a major role in reducing kappa(l) for Mg/Ca/Sr-alloyed PbTe through strongly suppressing the lifetimes of intermediate- and high-frequency phonons, while for Ba-alloyed PbTe, precipitated nanoparticles are also important. Published by MP Publishing.
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