Correlation effects on the electronic structure of Co2Mn0.5Fe0.5Si and Co2Mn0.5Gd0.5Si quaternary alloys

► Comparative study of the electronic structure calculated within GGA and GGA + U. ► 2-Correlation effects on the electronic and magnetic properties of quaternary alloys. ► Nearly half-metallic behavior was observed using GGA. ► Using GGA + U Co2Mn0.5Fe0.5Si and Gd in Co2Mn0.5Gd0.5Si are half-metallic.