Polarity control of spin-charge conversion in bulk Rashba semiconductor

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04846
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Condensed matter physics I
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Yoshimi Ryutaro 国立研究開発法人理化学研究所, 創発物性科学研究センター, 特別研究員 (40780143)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ラシュバ半導体 / 強磁性 / 電流誘起磁化反転 / スピントロニクス / 異常ホール効果

Outline of Final Research Achievements

We have attempted to control the polarity of charge-spin conversion through ferroelectric inversion by applying an electric field to ferromagnetic bulk Rashba semiconductor (Ge,Mn)Te, in which spatial inversion symmetry is broken by ferroelectricity. We have fabricated thin films of (Ge,Mn)Te by molecular beam epitaxy and demonstrated current-induced magnetization switching, which is a clear indication of spintronics functionality based on spin-polarized bulk bands of the material. Furthermore, we also established a method to control the carrier concentration in the sample by studying the thin film growth technique in detail, which is an important step to control the ferroelectric polarization by electric field.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

伝導電子によってスピン角運動量を生成するスピン電荷変換はこれまで数多く研究がなされてきたが、スピン角運動量の向きを電場によって変換する試みはこれまで行われてこなかった。本研究は強磁性ラシュバ半導体に着目してそのスピントロニクス特性を開発しただけでなく、上述の電場制御にまでアプローチした点において社会的意義がある。