Element-Specific Density Of States Of Co2mnge Revealed By Resonant Photoelectron Spectroscopy

Resonant photoelectron spectroscopy at the Co and Mn 2p core absorption edges of half-metallic Co2MnGe has been performed to determine the element-specific density of states (DOS). A significant contribution of the Mn 3d partial DOS near the Fermi level (E-F) was clarified by measurement at the Mn 2p absorption edge. Further analysis by first-principles calculation revealed that it has t(2g) symmetry, which must be responsible for the electrical conductivity along the line perpendicular to the film plane. The dominant normal Auger contribution observed at the Co 2p absorption edge indicates delocalization of photoexcited Co 3d electrons. The difference in the degrees of localization of the Mn 3d and Co 3d electrons in Co2MnGe is explained by the first-principles calculation. Our findings of the element-/orbital-specific electronic states near E-F will pave the way for future interface design of magnetic tunneling junctions to overcome the temperature-induced reduction of the magnetoresistance.