Unveiling the impurity band induced ferromagnetism in the magnetic semiconductor (Ga,Mn)As

作者：Kobayashi Masaki^*; Muneta Iriya; Takeda Yukiharu; Harada Yoshihisa; Fujimori Atsushi; Krempasky Juraj; Schmitt Thorsten; Ohya Shinobu; Tanaka Masaaki; Oshima Masaharu; Strocov Vladimir N

来源：Physical Review B, 2014, 89(20): 205204.

DOI：10.1103/PhysRevB.89.205204

(Ga,Mn)As is a paradigm of a diluted magnetic semiconductor which shows ferromagnetism induced by doped hole carriers. With a few controversial models emerging from numerous experimental and theoretical studies, the mechanism of the ferromagnetism in (Ga, Mn) As still remains a puzzling enigma. In this article, we use soft x-ray angle-resolved photoemission spectroscopy to positively identify the ferromagnetic Mn 3d-derived impurity band (IB) in (Ga, Mn) As. The band appears dispersionless and hybridized with the light-hole band of the host GaAs. These findings conclude the picture of the valence-band structure of (Ga, Mn) As disputed for more than a decade. The nondispersive character of the IB and its location in vicinity of the valence-band maximum indicate that the Mn 3d-derived IB is formed as a split-off Mn-impurity state predicted by the Anderson impurity model. Responsible for the ferromagnetism is predominantly the transport of hole carriers in the IB.

• 出版日期2014-5-19