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Strain Effects on the Electronic and Thermoelectric Properties of n(PbTe)-m(Bi2Te3) System Compounds

Authors :
Boulet, Weiliang Ma
Marie-Christine Record
Jing Tian
Pascal
Source :
Materials; Volume 14; Issue 15; Pages: 4086
Publication Year :
2021
Publisher :
Multidisciplinary Digital Publishing Institute, 2021.

Abstract

Owing to their low lattice thermal conductivity, many compounds of the n(PbTe)-m(Bi2Te3) homologous series have been reported in the literature with thermoelectric (TE) properties that still need improvement. For this purpose, in this work, we have implemented the band engineering approach by applying biaxial tensile and compressive strains using the density functional theory (DFT) on various compounds of this series, namely Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5. All the fully relaxed Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5 compounds are narrow band-gap semiconductors. When applying strains, a semiconductor-to-metal transition occurs for all the compounds. Within the range of open-gap, the electrical conductivity decreases as the compressive strain increases. We also found that compressive strains cause larger Seebeck coefficients than tensile ones, with the maximum Seebeck coefficient being located at −2%, −6%, −3% and 0% strain for p-type Bi2Te3, PbBi2Te4, PbBi4Te7 and Pb2Bi2Te5, respectively. The use of the quantum theory of atoms in molecules (QTAIM) as a complementary tool has shown that the van der Waals interactions located between the structure slabs evolve with strains as well as the topological properties of Bi2Te3 and PbBi2Te4. This study shows that the TE performance of the n(PbTe)-m(Bi2Te3) compounds is modified under strains.

Details

Language :
English
ISSN :
19961944
Database :
OpenAIRE
Journal :
Materials; Volume 14; Issue 15; Pages: 4086
Accession number :
edsair.multidiscipl..da5ebbad906353de2ef815df81526ae9
Full Text :
https://doi.org/10.3390/ma14154086