A DFT study of the electronic and magnetic properties of Fe2MnSi1−xGex alloys

Abstract

We performed density functional theory (DFT) calculations to study the structural, electronic and magnetic properties of Fe2MnSi1−xGex alloys (x=0, 0.25, 0.50, 0.75, and 1.00). The lattice constant is found to increase linearly as a function of Ge concentration with a decrease in the formation energy. The total magnetic moment is found to be 3μB for all alloys with the most contribution from Mn local magnetic moments. Iron atoms, however, exhibit much smaller spin moments about 10% of the bulk value. It seems that due to the proximity of Fe, magnetic moments have been induced on the sp atoms, which couple antiferromagnetically with Fe and Mn spin moments. Although, the band gap remains almost constant (0.5eV), the spin–flip gap decreases as a function of x.