First‐principles calculations to investigate structural stabilities, mechanical and optoelectronic properties of NbCoSn and NbFeSb half‐Heusler compounds

Abstract

The aim of this work was to study by means of the full potential linear muffin‐tin orbital method within generalized gradient approximation (GGA) and GGA + U approach the various physical properties of the NbCoSn and NbFeSb half‐Heusler compounds. The equilibrium ground states properties were calculated and compared with available experimental and theoretical data. The elastic constants have been calculated, and revealed that our compounds are mechanically stable. The obtained elastic modulus divulged that our compounds are elastically anisotropic and categorizing them as brittle compounds. The GGA approach showed a semi‐conductor nature. However, the GGA + U approach showed a significant improvement over other theoretical work. We remarked from the band structures that the two materials showed a p‐type semiconductor, with relatively high power factors. Furthermore, the optical quantities are calculated and discussed in detail. Hence, by our findings, the studied compounds could be used for thermoelectric and optoelectronic applications.

New insight into the structural, mechanical, electronic, and thermodynamic properties of the monoclinicTMAl3‐type aluminides

“…Here, the elastic properties of a solid have four key parameters: bulk modulus (B), shear modulus (G), Young's modulus (E), and Poisson ratio (σ) [59,60]. In particular, the elastic modulus of the monoclinic TMAl 3 aluminides are calculated by the elastic constants (C ij ) [61,62]. From the Hooke's rule, the elastic constants of the monoclinic TMAl 3 are calculated by [63]: These elastic constants of the monoclinic TMAl 3 are calculated by the total energy versus corresponding strain [64], which is given by:…”

Effects of Doping Ni on the Microstructures and Thermoelectric Properties of Co-Excessive NbCoSn Half-Heusler Compounds

“…38 A ferromagnetic order was assumed for all the systems, but for NbCoSn and Ni-excessive NbCoSn, their ground states converged to a nonmagnetic state. 39 The chemical disorder induced by Ni- substitution was simulated using the coherent potential approximation (CPA). 40−42 The application of CPA enables us to readily obtain the band structures of NbCoSn with interstitials using the primitive unit cell.…”

“…Total energy and band structure calculations were performed in the framework of DFT as implemented in the Exact Muffin-Tin Orbitals (EMTO) method. , The Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation was used for the exchange–correlation functional . A ferromagnetic order was assumed for all the systems, but for NbCoSn and Ni-excessive NbCoSn, their ground states converged to a nonmagnetic state . The chemical disorder induced by Ni-substitution was simulated using the coherent potential approximation (CPA). − The application of CPA enables us to readily obtain the band structures of NbCoSn with interstitials using the primitive unit cell.…”

Combined Experimental and First Principles Study on Nanostructured NbFeSb Half-Heusler Alloy Synthesized by Mechanical Alloying

“…Over the last few decades, Half-Heusler (HH) alloys have been drawing much attention of the material science community worldwide, both experimental and theoretical, for their potential utilities in sustainable energy related applications [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . They are among the most promising thermoelectric materials that can be used at medium to high temperature power generation purposes 9 .…”