New magnetic properties and a creation of next generation devices using Fe doped InAs/GaSb heterostructures

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04922
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Electron device/Electronic equipment
• Research Institution: The University of Tokyo
• Principal Investigator: Le Duc Anh 東京大学, 大学院工学系研究科(工学部), 助教 (50783594)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: Fe系強磁性半導体 / 室温強磁性 / スピンバルブ効果 / 近接磁気抵抗効果 / 奇関数磁気抵抗効果 / スピン三重項超伝導 / デルタドーピング / スピントランジスタ

Outline of Final Research Achievements

In this research, we investigate magnetic properties and device applications of Fe-based ferromagnetic semiconductors (FMSs). We successfully grew both p-type and n-type FMS with high Curie temperature (TC), which show an unprecedented tendency of higher TC in materials with narrower band gap. We elucidated the mechanisms of the strong ferromagnetism, band structures, and magnetic anisotropy in these Fe-based FMSs, from which we proposed a new design methodology towards high-TC FMSs. Furthermore, in several Fe doped GaSb/InAs heterostructures, we realized a spin-valve effect, and completely new phenomena such as giant proximity magnetoresistance and odd-parity magnetoresistance, which is crucial for device applications. With all of these virtues, our research has significantly advanced the field of spintronics. Last but not least, we realized a spin-triplet superconductivity in (In,Fe)As, which would pave a way towards a new hybrid research field of superconducting spintronics.

Free Research Field

スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

本研究はFe系強磁性半導体（FMS）で本来のFMSの問題をすべて克服しただけでなく、多くの固定観念を覆す結果も次々と発見した。特に大事な結果は高TCのFMS材料の実現に成功し、その強磁性発現機構及び材料設計指針を色々明らかになった。また本研究で初めて観測できた新しい磁気抵抗効果はどれも新規性と応用性が高い。このように本研究が半導体磁性全般を理論上と応用上の両側面で大きく前進させたと言える。更に、強磁性体と超伝導体を融合した新しい分野にパラダイムシフトすることも期待できる。半導体に「スピン」と「超伝導」を組み込むことより、今後求められる低消費電力や新機能を持つデバイスの創製に大きく貢献できる。