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arXiv · 2009.06285

Minority-Spin Impurity Band in n-Type (In,Fe)As: A Materials Perspective for Ferromagnetic Semiconductors

Masaki Kobayashi·Le Duc Anh·Jan Minar·Walayat Khan·Stephan Borek·Pham Nam Hai·Yoshihisa Harada·Thorsten Schmitt·Masaharu Oshima·Atsushi Fujimori·Masaaki Tanaka·Vladimir N. Strocov
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Abstract

Fully understanding the properties of n-type ferromagnetic semiconductors (FMSs), complementary to the mainstream p-type ones, is a challenging goal in semiconductor spintronics because ferromagnetism in n-type FMSs is theoretically non-trivial. Soft-x-ray angle-resolved photoemission spectroscopy (SX-ARPES) is a powerful approach to examine the mechanism of carrier-induced ferromagnetism in FMSs. Here our SX-ARPES study on the prototypical n-type FMS (In,Fe)As reveals the entire band structure including the Fe-3d impurity bands (IBs) and the host InAs ones, and provides direct evidence for electron occupation of the InAs-derived conduction band (CB). A minority-spin Fe-3d IB is found to be located just below the conduction-band minimum (CBM). The IB is formed by the hybridization of the unoccupied Fe-3d states with the occupied CBM of InAs in a spin-dependent way, resulting in the large spin polarization of CB. The band structure with the IB is varied with band filling, which cannot be explained by the rigid-band picture, suggesting a unified picture for realization of carrier-induced ferromagnetism in FMS materials.

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Masaki Kobayashi, Le Duc Anh, Jan Minar, Walayat Khan, Stephan Borek, Pham Nam Hai, Yoshihisa Harada, Thorsten Schmitt, Masaharu Oshima, Atsushi Fujimori, Masaaki Tanaka, Vladimir N. Strocov. 2020-09-14. Minority-Spin Impurity Band in n-Type (In,Fe)As: A Materials Perspective for Ferromagnetic Semiconductors. https://doi.org/10.1103/physrevb.103.115111

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