Formulation of bulk-edge correspondence in magnonic systems

• Project/Area Number: 15K13531
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Mathematical physics/Fundamental condensed matter physics
• Research Institution: Tohoku University
• Principal Investigator: Sato Koji 東北大学, 金属材料研究所, 助教 (70708114)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
• Keywords: マグノン / トポロジカル絶縁体 / スピン波 / ワイル半金属 / トポロジカル相 / ベリー曲率

Outline of Final Research Achievements

We theoretically investigated magnons for the purpose of understanding topological phenomena in bosonic systems. We found that conduction electrons coupled with magnons under dipolar interactions can exhibit anomalous Hall effect even in the absence of spin-orbit interactions. Moreover, we investigated Weyl semimetals motivated by a resemblance in a certain type of magnonic systems, and we clarified the structure of topological invariants in time-reversal symmetric Weyl semimetals.

Research Products

• [Journal Article] Tunable sign change of spin Hall magnetoresistance (2017)
  • Author(s): Dazhi Hou, Zhiyong Qiu, Joseph Barker, Koji Sato, Kei Yamamoto, Saul Velez, Juan M. Gomez-Perez, Luis E. Hueso, Felix Casanova, Eiji Saitoh
  • Journal Title: Physical Review Letters Volume: 118 Issue: 14 Pages: 147202-147202
  • DOI: 10.1103/physrevlett.118.147202
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Electrically controlled pinning of Dzyaloshinskii-Moriya domain walls (2016)
  • Author(s): K. Sato and Oleg A. Tretiakov
  • Journal Title: Applied Physics Letters Volume: 108 Issue: 12
  • DOI: 10.1063/1.4944664
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Anomalous Hall effect driven by dipolar spin waves in uniform ferromagnets (2015)
  • Author(s): Kei Yamamoto, Kojo Sato, Eiji Saitoh, Hiroshi Kohno
  • Journal Title: Physical Review B Volume: 92 Issue: 14 Pages: 140408-140408
  • DOI: 10.1103/physrevb.92.140408
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Electrically controlled pinning of Dzyaloshinskii-Moriya domain walls (2017)
  • Author(s): 佐藤浩司
  • Organizer: Regensburg-Tohoku Workshop on Tohoku Solid State Physics
  • Place of Presentation: 山形市
  • Year and Date: 2017-03-28
  • Int'l Joint Research / Invited
• [Presentation] Anomalous Hall effect driven by dipolar spin waves in uniform ferromagnets (2016)
  • Author(s): Kei Yamamoto, Koji Sato, Eiji Saitoh, Hiroshi Kohno
  • Organizer: APS March Meeting
  • Place of Presentation: Baltimore, USA
  • Year and Date: 2016-03-15
  • Int'l Joint Research
• [Presentation] Anomalous Hall effect driven by dipolar spin waves in uniform ferromagnets (2015)
  • Author(s): Koji Sato
  • Organizer: Mathematical Approach to Topological Phases in Spintronics
  • Place of Presentation: 東北大学（宮城県・仙台市）
  • Year and Date: 2015-10-08
  • Int'l Joint Research / Invited