Unveiling spin-dependent unoccupied electronic states of CoMnGe (Ga) film via Ge (Ga) absorption spectroscopy

Yoshikawa, Tomoki*; Antonov, V. N.*; Kono, Takashi*; Kakoki, Masaaki*; Sumida, Kazuki   ; Miyamoto, Koji*; Takeda, Yukiharu   ; Saito, Yuji  ; Goto, Kazuki*; Sakuraba, Yuya*; Hono, Kazuhiro*; Ernst, A.*; Kimura, Akio*

X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy were applied at the Ge (Ga) edge to unravel the spin-resolved unoccupied electronic states of CoMnGe (Ga). Complicated spectral features were observed in both XAS and XMCD spectra. For their interpretation, we compared the experimental XAS and XMCD spectra with the calculated Ge (Ga) 4 and 4 orbital partial density of states. The comparison enabled a qualitative explanation of the XMCD spectra as the difference between the majority and minority-spin unoccupied density of states summed over the 4 and 4 orbitals. Our finding provides a new approach to uncover the spin-split partial density of states above the Fermi level.