強磁性半導体の世界最高のキュリー温度を実現～スピン機能半導体デバイスの実現へ前進～

2025-05-27 東京科学大学

図1. 通常の半導体と強磁性半導体の結晶構造

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• https://pubs.aip.org/aip/apl/article-abstract/126/16/162407/3345196/Very-high-Curie-temperature-470-530-K-in-Ga-Fe-Sb?redirectedFrom=fulltext

近接GaAs基板上にステップフローモードで成長した(Ga,Fe)Sb強磁性半導体の非常に高いキュリー温度(470-530 K)
Very high Curie temperature (470–530 K) in (Ga,Fe)Sb ferromagnetic semiconductor grown by step-flow mode on vicinal GaAs substrates

Pham Nam Hai ;Ken Takabayashi;Kota Ejiri;Masaaki Tanaka
Applied Physics Letters  Published:April 24 2025
DOI:https://doi.org/10.1063/5.0227990

Narrow-gap Fe-doped III–V ferromagnetic semiconductors (FMSs), such as (In,Fe)Sb, (Ga,Fe)Sb, and (In,Fe)Sb, are promising candidates for active semiconductor spintronic devices thanks to their high Curie temperature (T_C). In this work, we show that by growing (Ga,Fe)Sb thin films by the step-flow mode on vicinal GaAs (100) substrates with a high off-angle of 10°, we can achieve high-quality (Ga_0.76,Fe_0.24)Sb FMS with T_C as high as 470–530 K, which are the highest T_C reported so far for FMSs. The magnetic moment of Fe atoms in our sample reaches 4.5 μ_B/atom, which is close to the ideal magnetic moment of substitutional Fe³⁺ atoms (5 μ_B/atom) in a zinc blende crystal structure, and is twice that of α-Fe metal. Our work establishes a growth technique of very high T_C FMSs for room-temperature semiconductor spintronic devices.