A quest of a novel Hall effect, topological planar Hall effect

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18755
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics and related fields
• Research Institution: Kyoto University
• Principal Investigator: Shiraishi Masashi 京都大学, 工学研究科, 教授 (30397682)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: トポロジカル絶縁体 / プレーナーホール効果 / 強磁性体

Outline of Final Research Achievements

A study for a quest of a novel Hall effect, the topological planar Hall effect, has been carried out by fabricating topological insulator(TI)/normal insulator(I)/ferromagnet(FM) trilayer systems. However, a trade-off effect was found by the study, i.e. strong normal insulator kills the coupling of the TI and the FM and weak normal insulator kills topological states of TIs due to the magnetic field from the FM. So, it was not easy to observe the effect successfully in the research time period.

Meanwhile, it is quite significant that topological spin conversion with Onsager reciprocity up to room temperature was successfully achieved.

Free Research Field

固体物理

Academic Significance and Societal Importance of the Research Achievements

トポロジカル物性は21世紀に勃興した最先端の物理学領域であるだけでなく、従来の物性物理学だけでなく、高エネルギー物理学・位相幾何学なども包括する新しい学術領域である。この新学術領域の地平を、トポロジカルなスピン変換をオンサーガーの相反定理を満たす形で計測することで広げることができたことは極めて意義深い。