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- Title
Thermoelectric Properties of FeVAl and FeVMAl (M = Mo, Nb, Ta) Alloys: First-Principles Calculations.
- Authors
Al-Yamani, H.; Hamad, B.
- Abstract
Ab initio investigations of the structural, electronic, and thermoelectric properties of stoichiometric FeVAl full-Heusler alloy and FeVMAl (M = Mo, Nb, Ta) nonstoichiometric alloys have been performed using density functional theory on the basis of the full-potential linearized augmented plane wave method with the generalized gradient approximation. The thermoelectric properties are calculated using semiclassical Boltzmann transport theory within the constant-relaxation-time approximation. FeVAl, FeVNbAl, and FeVTaAl alloys are found to exhibit a semimetallic behavior, while FeVMoAl acts as a metal. We found that FeVAl has a pseudogap of about −0.13 eV, whereas FeVNbAl and FeVTaAl are characterized by a zero energy gap around the Fermi level. Thermoelectric calculations showed that FeVAl has both p- and n-type thermoelectric properties, where the p-type thermopower values are found to be higher than those of n-type. The Seebeck coefficient S has maximum values from 20 μV K to 125 μV K and from 19 μV K to 90 μV K in the temperature range of 100 K to 800 K for p- and n-type, respectively. The maximum thermoelectric properties can be obtained at carrier concentration of the order of 10 cm for p- or n-type doping. Substitution of Nb and Ta atoms enhanced the thermoelectric properties to 150 μV K at 800 K. The optimum concentrations for the three partially substituted alloys were found to be between 10 cm and 10 cm.
- Subjects
IRON-molybdenum alloys; IRON-aluminum alloys; THERMOELECTRIC effects; VANADIUM alloys; BAND gaps; BOLTZMANN'S equation; FERMI level
- Publication
Journal of Electronic Materials, 2016, Vol 45, Issue 2, p1101
- ISSN
0361-5235
- Publication type
Article
- DOI
10.1007/s11664-015-4265-8