Theoretical study of the structural stability, electronic and magnetic properties of XVSb (X = Fe, Ni, and Co) half-Heusler compounds

Mokhtari Mokhtari,Benabdellah Benabdellah,Zekri Zekri,Benalia Benalia,Dahmane Dahmane

doi:10.5488/cmp.21.43705

Abstract

The structural, electronic and magnetic properties of half-Heusler compounds XVSb (X $=$ Fe, Co and Ni) are investigated by using the density functional theory with generalized gradient approximation (GGA), and Tran-Blaha modified Becke-Johnson (TB-mBJ) exchange potential approximation. It is found that the half-metallic gaps are generally reasonably widened by mBJ as compared to the GGA approximation. The magnetic proprieties of XVSb (X $=$ Fe, Co and Ni) are well defined within mBJ with an exact integer value of magnetic moment. The band gaps given by TB-mBJ are in good agreement with the available theoretical data. The FeVSb exhibits a semiconductor nature. The CoVSb and NiVSb present half-metallic behaviour with total magnetic moment of $1\mu_\text{B}$ and $2\mu_\text{B}$ in good agreement with Slater-Pauling rule. These alloys seem to be a potential candidate of spintronic devices.

Highlights

A motivating group of ternary alloys having chemical formula XYZ named as half-Heusler (HH) compounds, crystallize in the face centered cubic structure [1, 2], where X is rare-earth or transition metal, Y is transition metal and Z is the main group element [3]
In the half-Heusler C1b structure, the XVSb adopts three possible arrangements named phase α, phase β and phase γ in theory, and these atomic arrangements are possible, which should be distinguished, if electronic structure calculations are executed, since the correct site assignment is important for the obtained electronic structure [20]
In order to define the correct arrangement of the atomic positions in the crystal and the ground state properties, such as the equilibrium lattice constant (a), bulk modulus (B) and its pressure derivative (B ), the structural optimization of three XVSb (X = Fe, Co and Ni) compounds was performed by minimizing the total energy with respect to the lattice parameter variation

Summary

Introduction

A motivating group of ternary alloys having chemical formula XYZ named as half-Heusler (HH) compounds, crystallize in the face centered cubic structure (space group F43m; No 216) [1, 2], where X is rare-earth or transition metal, Y is transition metal and Z is the main group element [3] These materials have been of large interest to both experimental and theoretical researchers since they were first studied by Andreas Heusler [4]. The electronic density of states (DOS) at EF of an ideal half-metal is composed of only one spin direction resulting in a very high spin polarization ratio at Fermi level These compounds (half-metals) are efficient to employ in the conduction of spin polarized current due to its great sensitivity to the applied magnetic field. These types of materials have many technological applications, such as spintronics [8, 9] and spin injection to semiconductors [10, 11]

Methods

Results

Conclusion