Optical, half-metallic and thermoelectric properties of the Co2TaAl [001] film

• Published in: Indian journal of physics Vol. 95; no. 9; pp. 1709 - 1721
• Main Authors: Mohebbi, Reza, Boochani, Arash, Rezaee, Sahar
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.09.2021; Springer Nature B.V
• Subjects: Astrophysics and Astroparticles; Bulk modulus; Density functional theory; Doppler effect; Energy gap; Fermi surfaces; High temperature; Magnetic moments; Optical properties; Original Paper; Phase diagrams; Physics; Physics and Astronomy; Polarization (spin alignment); Power factor; Red shift; Thermoelectricity; Half-metallic properties; DFT; Thermoelectric Properties; Optical properties; Co2TaAl film
• ISSN: 0973-1458; 0974-9845
• DOI: 10.1007/s12648-020-01836-x

Based on the density functional theory framework and GGA approximation, the structural, electronic, optical and thermoelectric properties of the Co 2 TaAl and its [001] films have been calculated. The Co 2 TaAl compound has great hardness with the bulk modulus of 201.5 GPa which is bigger than steel. This compound has half-metallic nature with 100% spin polarization in the Fermi surface and 2.0 µ B magnetic moment. Due to its the real and imaginary dielectric function responses in the visible region and very low Eloss and extinction, this compound is a suitable case for optical applications in visible area energy. The Co 2 TaAl, also has a suitable thermoelectric efficiency in all temperatures, for a spin down with big power factor in high temperatures which is suitable for power generation applications. The energy-volume and thermodynamic phase diagrams of the [001] films are indicate, their stability, in the mechanical and thermodynamic views. The electronic diagrams showed the half-metallic behavior of the TaAl termination with 100% spin polarization, by the 0.25 eV energy gap in the down spin. The optical response of the TaAl termination for the E ⊥ z direction is similar to that of the bulk case and has a red shift, but in the E ∥ z the metallic nature is reduced. The merit amount of the TaAl termination is 0.7 in the lower temperatures for a down spin and its Seebeck has been greater than that of the bulk case.