Study on spin polarization of non-magnetic atom in diluted magnetic semiconductor: The case of Al-doped 4H–SiC

highlights
• The atomic origin of the magnetism in Al-doped 4H–SiC was pinpointed.
• Electron magnetic circular dichroism signals were observed in nonmagnetic C atoms.
• No electron magnetic circular dichroism signals were observed in Si and Al atoms.
• The spin polarization of C atoms was confirmed by first principles calculations.

Determining the atomic origin of magnetism in non-magnetic elements doped dilute magnetic semiconductors (DMS) is a key issue to understand the room temperature ferromagnetism. Here, using electron magnetic circular dichroism (EMCD), an element-selectivity and high spatial resolution technique, we provide unambiguous experimental evidence: spin polarization of carbon atoms contributes to the local magnetic moments of Al-doped 4H–SiC DMS. The result is further confirmed by first-principle calculations.