Density Functional Theory(DFT) Study of Alkali-Metal-Based Half-Heusler Compound NaCrSb

Abstract

In this study we investigated half-heusler alloy (NaCrSb) using density functional theory as implemented in Quantum espresso software version qe-6.8 for simulation on ubuntu operating system version 22.04LTS. The Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) was used for the exchange-correlation potential. The projector augmented-wave (PAW) method was employed to described the core electrons. The Quantum ESPRESSO input file used sets up a self-consistent field (SCF) calculation for a spin-polarized system within a face-centered cubic (fcc) lattice structure.  The electrons section focuses on convergence settings for the SCF procedure, specifying the mixing factor (mixing_beta) and the diagonalization algorithm (Davidson). The atomic species and atomic positions sections detail the types of atoms present, their masses, and the corresponding pseudopotentials.  The material NaCrSb is structurally stable from studied at beta (β)-phase. The half-Heusler alloy has measured band gap of 1.93eV was obtained for NaCrSb, with a range of values. This indicates that NaCrSb is an indirect bandgap semiconductor material. The compound NaCrSb exhibits behavior during spin up and down that is characteristic of both metals and semiconductors, which foretells the half-metallic Heusler alloy. The B/G ratio of 2.53 indicates that the NaCrSb material is ductile. The material's resistance to impact is addressed holistically by the Vicker's hardness. Na-1s and Na-3s; Cr-1s, Cr-2p, Cr-3s; and Sb-1s, Sb- 2s, Sb - 3p has high orbital contribution for the Na,Cr, and Sb-atoms. At fermi energy  both the spin up and spin down is at zero point in plot of partial density of state(PDOS) against energy. It became vivid from this that NaCrSb is a half-metallic Heusler alloy. Positive frequencies were detected in the phonon dispersion curves along the r - X - K - r - L - W - X high symmetry directions. This suggests that NaCrSb is dynamically stable. The search for new materials with special qualities is what propels progress in materials research and technology.