Density functional study of the half-metallic ferromagnetism in Co-based Heusler alloys Co_2MSn (M = Ti, Zr, Hf) using LSDA and GGA

摘要

The half-metallic state in the Heusler alloys Co_2MSn (M = Ti, Zr, Hf) was studied by means of first principles calculation, using both, the Local Spin Density Approximation (LSDA) and the Generalized Gradient Approximation (GGA) to the exchange-correlation energy. While the GGA calculation shows that the three alloys are half-metallic ferromagnets, the LSDA results show that they are ferromagnetic but not half-metallic systems. The difference between the exchange-correlation functionals is analyzed through the electronic structure of the alloys. The origin of the gap in the minority spin channel for GGA calculations is discussed.