Polarity control of spin-charge conversion in bulk Rashba semiconductor

• 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
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥25,870,000 (Direct Cost: ¥19,900,000、Indirect Cost: ¥5,970,000); Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2018: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2017: ¥19,760,000 (Direct Cost: ¥15,200,000、Indirect Cost: ¥4,560,000)
• 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 / ラシュバ効果 / マルチフェロイクス / 磁性半導体 / 物性実験 / ラシュバ系

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.

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。

Research Products

• [Journal Article] Nonreciprocal charge transport at topological insulator/superconductor interface (2019)
  • Author(s): Yasuda Kenji、Yasuda Hironori、Liang Tian、Yoshimi Ryutaro、Tsukazaki Atsushi、Takahashi Kei S.、Nagaosa Naoto、Kawasaki Masashi、Tokura Yoshinori
  • Journal Title: Nature Communications Volume: 10 Issue: 1 Pages: 1-6
  • DOI: 10.1038/s41467-019-10658-3
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Quantum anomalous Hall effect driven by magnetic proximity coupling in all-telluride based heterostructure (2019)
  • Author(s): Watanabe R.、Yoshimi R.、Kawamura M.、Mogi M.、Tsukazaki A.、Yu X. Z.、Nakajima K.、Takahashi K. S.、Kawasaki M.、Tokura Y.
  • Journal Title: Applied Physics Letters Volume: 115 Issue: 10 Pages: 102403-102403
  • DOI: 10.1063/1.5111891
  • Peer Reviewed
• [Journal Article] Current-driven magnetization switching in ferromagnetic bulk Rashba semiconductor (Ge,Mn)Te (2018)
  • Author(s): Yoshimi R.、Yasuda K.、Tsukazaki A.、Takahashi K. S.、Kawasaki M.、Tokura Y.
  • Journal Title: Science Advances Volume: 4 Issue: 12 Pages: 9989-9989
  • DOI: 10.1126/sciadv.aat9989
  • Peer Reviewed / Open Access
• [Presentation] Magnetic and superconducting proximity effect at the interface of topological materials (2019)
  • Author(s): R. Yoshimi
  • Organizer: EPiQS-TMS alliance WS
  • Int'l Joint Research / Invited
• [Presentation] Quantum anomalous Hall effect by magnetic proximity coupling (2019)
  • Author(s): R. Yoshimi
  • Organizer: CEMS Symposium on Emergent Quantum Materials
  • Int'l Joint Research
• [Presentation] 磁気近接相互作用による 量子異常ホール効果の観測 (2019)
  • Author(s): 吉見龍太郎, 渡邊竜太, 川村稔, 茂木将孝, 塚﨑敦, 于秀珍, 中島清美, 高橋圭, 川﨑雅司, 十倉好紀
  • Organizer: 日本物理学会2019年秋季大会
• [Presentation] Unidirectional magnetoresistance in a bulk Rashba ferromagnet (2019)
  • Author(s): R. Yoshimi, K. Yasuda, A. Tsukazaki, M. Kawamura, K. S. Takahashi, M. Kawasaki and Y. Tokura
  • Organizer: American Physical Society
  • Int'l Joint Research
• [Presentation] 極性強磁性半導体Ge1-xMnxTeにおける電流誘起磁化反転 (2018)
  • Author(s): 吉見龍太郎, 安田憲司, 塚崎敦, 高橋圭, 川崎雅司, 十倉好紀
  • Organizer: 日本物理学会2018年年次大会
• [Presentation] Current-driven magnetization reversal in a Rashba bulk ferromagnet (2018)
  • Author(s): R. Yoshimi, K. Yasuda, A. Tsukazaki, K. S. Takahashi, M. Kawasaki and Y. Tokura
  • Organizer: American Physical Society, March Meeting
• [Presentation] Current-induced magnetization switching in bulk Rashba ferromagnet (2017)
  • Author(s): R. Yoshimi, K. Yasuda, A. Tsukazaki, K. S. Takahashi, M. Kawasaki and Y. Tokura
  • Organizer: CEMS Symposium on Trends in Condensed Matter Physics
• [Remarks] マルチフェロイクス材料における電流誘起磁化反転を実現 －低消費電力エレクトロニクスへの新原理を構築－
  • URL: http://www.riken.jp/pr/press/2018/20181208_1/