This work investigates the quaternary Heusler alloy CoFeZrSi using a first-principles approach to assess its potential for spintronic and optoelectronic applications. Heusler compounds are of significant interest due to their versatile electronic and magnetic properties, particularly their ability to exhibit half-metallic ferromagnetism, which is essential for efficient spintronic devices. This study aims to provide a comprehensive understanding of CoFeZrSi by examining its structural, electronic, magnetic, mechanical, and optical behaviors.

Calculations were performed within the framework of density functional theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code. Three atomic arrangements based on the F-43m space group (Y1, Y2, and Y3) were analyzed. Structural optimization revealed that the Y1-type configuration is the most energetically favorable. Electronic properties were computed using both the generalized gradient approximation (GGA-PBE) and the modified Becke–Johnson (TB-mBJ) potential.

The results show that CoFeZrSi exhibits half-metallic ferromagnetism with an indirect band gap of 0.657 eV (GGA) and 1.451 eV (TB-mBJ) in the minority-spin channel. The total magnetic moment is 1 μB per formula unit, in accordance with the Slater–Pauling rule. Elastic constants confirm mechanical stability and ductility, with favorable values of bulk modulus, shear modulus, Poisson’s ratio, and Pugh’s ratio.

Optical analyses indicate strong interband transitions and high absorption in the visible and ultraviolet ranges, as evidenced by the dielectric function, absorption coefficient, and energy loss spectra.

In conclusion, CoFeZrSi demonstrates robust half-metallicity, mechanical reliability, and strong optical activity, suggesting it is a promising candidate for use in next-generation spintronic and optoelectronic technologies.

References:

1. Ş. Ţălu, Micro and nanoscale characterization of three dimensional surfaces. Basics and
applications. Napoca Star Publishing House, Cluj-Napoca, Romania, 2015.