Enhanced thermoelectric performance of a quintuple layer of Bi{sub 2}Te{sub 3}

Journal Article · Mon Jul 14 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4889921· OSTI ID:22308726

Zhang, J.; Cheng, L.; Wei, J.; Shi, J. ^[1]; Tang, X. F. ^[2]; Uher, C. ^[3]

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1. Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)
2. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)
3. Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

The electronic structure of a quintuple layer (QL) of Bi{sub 2}Te{sub 3} is calculated using the first-principles pseudopotential method. It is found that the band gap of an isolated QL is considerably larger than that of bulk Bi{sub 2}Te{sub 3}. The electronic transport of the QL is, then, evaluated using the semiclassical Boltzmann theory within the relaxation time approximation. By fitting the energy surface from first-principles calculations, a suitable Morse potential is constructed and used to predicate the lattice thermal conductivity via equilibrium molecular dynamics simulations. By optimizing the carrier concentration of the system, the ZT of Bi{sub 2}Te{sub 3} QL can be enhanced to a relatively high value. Moreover, the ZT value exhibits strong temperature dependence and can reach as high as 2.0 at 800 K. This value can be further increased to 2.2 by the substitution of Bi atoms with Sb atoms, giving nominal formula of (Bi{sub 0.25}Sb{sub 0.75}){sub 2}Te{sub 3}. The significantly enhanced ZT value makes QL a very appealing candidate for thermoelectric applications.

• OSTI ID: 22308726
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 2; Other Information: (c) 2014 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
ATOMS
BISMUTH TELLURIDES
CARRIERS
CONCENTRATION RATIO
ELECTRONIC STRUCTURE
LAYERS
MOLECULAR DYNAMICS METHOD
MORSE POTENTIAL
OPTIMIZATION
RELAXATION TIME
SEMICLASSICAL APPROXIMATION
SIMULATION
SURFACES
TEMPERATURE DEPENDENCE
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES