Structural, Elastic, Electronic, Magnetic and Optical Properties of Spin Gapless Semiconducting Heusler Alloy Ti2FeSb Using First-Principles Calculations

Density functional theory has been used to study the structural, elastic, electronic, magnetic and optical properties of Ti2FeSb Heusler alloy using generalised gradient approximation implemented through the WIEN2k code. The cubic structure of Ti2FeSb is mechanically stable in the F-43m space group and shows elastic anisotropic properties with ductile nature. Ti2FeSb shows spin gapless semiconductor behaviour along with an indirect energy band gap (E-G) of 0.10 eV along the ?-Chi in majority spin (gamma-spin) band above the Fermi energy level (E-F) and 0.90 eV in the minority spin (delta-spin) band at E-F. The total magnetic moment is 3 mu(B) at optimized lattice constant (a(o)) 6.32 angstrom and follows the Slater-Pauling curve for inverse Heusler alloys. Robustness of this material with respect to change in the value of a(o) is evident in the constancy of magnetic moment along with retention of the half metallic nature within a lattice variation +/- 4% from equilibrium value of a(o). Reflectivity, optical conductivity, dielectric function, absorption coefficient and energy loss have also been investigated as a function of incident energy for this alloy.