Using a well-focused soft X-ray synchrotron radiation beam, angle-resolved photoelectron spectroscopy was applied to a full-Heusler-type Co2MnGe alloy to elucidate its bulk band structure. A large parabolic band at the Brillouin zone center and several bands that cross the Fermi level near the Brillouin zone boundary were identified in line with the results from first-principles calculations. These Fermi-level crossings are ascribed to majority spin bands that are responsible for electron transport with extremely high spin polarization especially along the direction perpendicular to the interface of magnetoresistive devices. The spectroscopy confirms there is no contribution of the minority spin bands to the Fermi surface, signifying half-metallicity for the alloy. Furthermore, two topological Weyl cones with band crossing points were identified around the X point, yielding the conclusion that Co2MnGe could exhibit topologically meaningful behavior such as large anomalous Hall and Nernst effects driven by the Berry flux in its half-metallic band structure.
ASJC Scopus subject areas
- Physics and Astronomy(all)