First-Principles Investigation of the Structural, Magnetic, Electronic, and Optical Properties of FeMnScB Quaternary Heusler Alloy
Abstract
The structural, magnetic, electronic and optical properties of FeMnScB quaternary Heusler alloys (QHA) investigated using spin polarised density function theory within the full potential linearised augmented plane wave (FP-LAPW) method considering the Perdew- Burke-Ernzerhof Generalized Gradient Approximation (PBE-GGA) exchange correlation functional using WIEN2K. Ferromagnetic (FM) configurations are energetically more favorable than antiferromagnetic (AFM) and non-magnetic (NM) states, according to total energy calculations, establishing the FM phase as a magnetic ground state. Excellent structural stability is indicated by the optimized equilibrium lattice parameter of 5.7559 Å and a bulk modulus of 165.4369 GPa. The Slater-Pauling rule is followed by the computed total magnetic moment of 3.00 μB per formula unit, and the magnetic moment shows strong magnetic stability. A highly spin-polarized electronic state with ~99.33% spin polarization at the Fermi level and a small minority-spin energy gap of 0.31 eV is revealed by electronically computed band structure, indicating near-half-metallic behavior. Fe-3d and Mn-3d orbitals dominate the magnetic and electronic properties, according to orbital-resolved density of states studies, whereas Sc mainly serves as an electron donor and B enhances chemical bonding and structural stability through p-d hybridization. Throughout the visible and ultraviolet (UV) spectrum, optical constants show substantial absorption coefficients (~10 4 cm -1 ), notable optical conductivity, moderate reflectivity, and a prominent dielectric response, all of which point to effective photon absorption and carrier activation. FeMnScB is a promising multifunctional QHA for advanced spintronic, magneto-optoelectronic, UV photonic, and photovoltaic applications due to its structural durability, intrinsic ferromagnetism, high spin polarization, and broadband optical activity.