Document Type : Research
Author
Faculty member, Shiraz University of Technology
Abstract
A B S T R A C T
We present a comparative study based on Density Functional Theory (DFT), of the effect that different approximations such as exchange-correlation (XC) functional, effect of Hubbard U, TB-mBJ correction and optimized lattice constant strain have on the structural and electronic properties of NaTiAs compound. At first, by using DFT based full-potential WIEN2k package we compare the total energy vs volume of ferromagnetic, antiferromagnetic and non-magnetic half-Heusler structures to obtain the more stable configuration phase and magnetic state. Calculations show that our compound is more stable in the half-Heusler beta-phase and the ferromagnetic state. Then, we investigate the structural and electronic properties of NaTiAs-beta by using LDA, PBEsol, WC and PBE XC functionals. Our results show that different XC functionals cannot lead to half metallicity. But when we use the GGA+U and TB-mBJ schemes with PBE parameterization, results indicate that the Fermi level cuts through the partially occupied band in majority spin channel while it is located in the gap between valence and conduction bands in the minority spin direction thus it demonstrates the half-metallic behavior of this compound, and the amount of a total magnetic moment is equal to . Furthermore, by applying at least optimized lattice constant strain, NaTiAs-beta becomes half metal. Examination of the elastic constants shows that the compound is stable. These types of compounds are candidates for making spintronic devices.
Keywords
)