The electronic structure and thermoelectric properties of BiTl{sub 9}Te{sub 6} and SbTl{sub 9}Te{sub 6}: First-principles calculations

Journal Article · Mon Dec 21 00:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4938058· OSTI ID:22493078

Guo, Li Bin; Ye, Lingyun; Yang, Jue Ming; Yan, Yu Li; Ren, Feng Zhu ^[1]

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1. Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

The electronic structure and thermoelectric properties of MTl{sub 9}Te{sub 6} (M = Bi, Sb) were studied using density functional theory and the semiclassical Boltzmann theory. It is found that the band gaps of BiTl{sub 9}Te{sub 6} and SbTl{sub 9}Te{sub 6} are equal to 0.59 eV and 0.72 eV, respectively. The relative large band gap and strong coupling between Sb s and Te p are helpful to the thermoelectric properties of SbTl{sub 9}Te{sub 6}. Near the bottom of the conduction bands, the number of band valleys of SbTl{sub 9}Te{sub 6} is four and is larger than that of BiTl{sub 9}Te{sub 6} (two band valleys), which will increase its Seebeck coefficient. Although BiTl{sub 9}Te{sub 6} has a larger electrical conductivity relative to relaxation time (σ/τ) along the z-direction than that of SbTl{sub 9}Te{sub 6}, the results show that the transport properties of SbTl{sub 9}Te{sub 6} are better than those of BiTl{sub 9}Te{sub 6} possibly due to its large Seebeck coefficient. The maximum value of power factor relative to relaxation time (S{sup 2}σ/τ) for SbTl{sub 9}Te{sub 6} reaches 4.30 × 10{sup 11 }W/K{sup 2} m s at 900 K, that is, originated from its relatively large Seebeck coefficient, suggesting its promising thermoelectric performance at high temperature.

• OSTI ID: 22493078
• Journal Information: Journal of Applied Physics, Vol. 118, Issue 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
74 ATOMIC AND MOLECULAR PHYSICS
ANTIMONY
ANTIMONY COMPOUNDS
BISMUTH
BISMUTH COMPOUNDS
BOLTZMANN EQUATION
DENSITY FUNCTIONAL METHOD
ELECTRIC CONDUCTIVITY
ELECTRONIC STRUCTURE
EV RANGE
POWER FACTOR
RELAXATION TIME
SEEBECK EFFECT
SEMICLASSICAL APPROXIMATION
STRONG-COUPLING MODEL
TEMPERATURE RANGE 0400-1000 K
THERMOELECTRIC PROPERTIES