Visualizing Half-Metallic Bulk Band Structure with Multiple Weyl Cones of the Heusler Ferromagnet

Takashi Kono, Masaaki Kakoki, Tomoki Yoshikawa, Xiaoxiao Wang, Kazuki Goto, Takayuki Muro, Rie Y. Umetsu, Akio Kimura

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Article number216403
JournalPhysical review letters
Volume125
Issue number21
DOIs
Publication statusPublished - 2020 Nov 19

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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