Thermoelectric and half-metallic behavior of the Co2TaAl: a DFT study

• Published in: International nano letters Vol. 10; no. 2; pp. 81 - 88
• Main Authors: Mohebbi, Reza, Boochani, Arash, Rezaee, Sahar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2020; Springer Nature B.V
• Subjects: Absorption spectra; Chemistry and Materials Science; Density functional theory; Energy gap; Hydrostatic pressure; Materials Science; N-type semiconductors; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Optical properties; Original Article; P-type semiconductors; Thermoelectricity; Thermoelectric; DFT; Co; Thermodynamic phase diagram; Half-metal; TaAl
• ISSN: 2008-9295; 2228-5326
• DOI: 10.1007/s40089-020-00296-9

The electronic, thermoelectric, optical and thermodynamic stability of the full-Heusler compound Co 2 TaAl is investigated under hydrostatic pressure in the range of (25.4 to − 26.3 GPa) within the framework of the density functional theory and the semi-classical Boltzmann theory using the generalized gradient approximation. The Co 2 TaAl compound in the minority spin is an n -type semiconductor with an indirect band gap of about 0.78 eV along Γ – X direction and a spin-flip gap of 0.6 eV. Applying stress led to decreasing the band gap turning the material to a p -type semiconductor; however, it remained n -type but with zero spin-flip gap under strain. The dimensionless Merit coefficient for the spin dn channel of Co 2 TaAl at equilibrium pressure obtained a large value of 0.98 at temperatures below 500 K. The optical properties of this compound, including refraction and reflection coefficients, absorption spectra, and real and imaginary parts of the dielectric function are studied in detail.