Abstract
The electronic structure of Co-based quaternary Heusler compounds Co2CrAl1-xSix (x=0.00, 0.25, 0.50, 0.75, 1.00) is calculated by first-principles density functional theory. The substitution of Al by Si leads to increase in the number of valence electrons which causes decrease in lattice constant and increase in bulk modulus and total magnetic moment. It shows that the properties of the compound are dependent on electron concentration of main group element. The calculations reveal that the alloys with x=0.75, 1.00 exhibit 100% spin polarization at the Fermi level.