Study of electronic structure of Co2MnSn Heusler alloy by resonant photoemission spectroscopy and ab initio calculations

Abstract

The electronic structure of a ferromagnetic Heusler alloy Co2MnSn has been investigated using resonant photoemission spectroscopy to probe the Mn 3d and Co 3d states in the valence band region. The motivation of the present work is to understand the low value of spin polarization reported for this system, which mainly depends on the density of states present at the Fermi level. Valence band of Co2MnSn shows a large density of delocalized Co 3d states present near the Fermi level. The Mn 3d states are more localized and exist below the Fermi level. First principles calculations using density functional theory with GGA and GGA+U formalisms have been performed to understand and analyze the experimental results. The experimental density of states and magnetic moment show a good matching with the calculation carried out with on-site Coulomb correlation U of ∼3eV on the Mn 3d states. The presence of U on the Mn 3d states also reduces the spin polarization at the Fermi level, which is one of the reasons for the observed low value of spin polarization reported for this system.