2020年度 提案書 （Web公開用）

作成者： DUTTAGUPTA SAMIK（東北大CSIS）

研究プロジェクト名： Charge and spin‐dependent topologicaltransport phenomena in antiferromagnetic Weyl semi‐metals
概要： The interplay of relativistic spin‐orbit interaction, electronic band topology, and magnetic
order in antiferromagnetic Weyl semi‐metals (WSMs) manifests in novel properties prospective for
antiferromagnetic spintronics. We aim to quantify the magnetotransport properties ofantiferromagnetic WSM and WSM/non‐magnet heterostructures. Our experimental results,
supported by semiclassical modelling will provide a convenient approach for understanding of themanifestations of band topology in WSMs, crucial for topological antiferromagnet spintronics.

コアメンバー： Samik DuttaGupta (CSIS, Tohoku Univ), Shunsuke Fukami (RIEC,Tohoku Univ), Yuta Yamane (FRIS, Tohoku Univ.), Jun’ichi Ieda (JAEA)
期待される研究成果：
The results obtained from this research entails
the clarification of electronic transportphenomena associated with non‐trivial
topological band characteristics and spin‐structures in WSM heterostructures. This will
provide an electrical probe to access therelativistic effects arising from Berry curvatureand topological Dirac or Weyl points in thinfilm Weyl semimetals. The proposed
experimental and theoretical investigations is
crucial for development of topologicalantiferromagnetic spintronics.

(a)

(b)

Cap
Weyl semimetal
Underlayer

Figure: (a) Schematic diagram of the Weyl semimetal antiferromagnet hall bar
structure. IDC refers to the applied current while VXY is the measured voltage
under the application of external magnetic field rotated in the x-y plane (θXY).
(b) Experimental results of Hall resistivity (ρXY) versus θXY under µ0H = 6T at
RT demonstrates the existence of a planar Hall effect originating from a chiralmagnetic effect arising from the topological nature of the electronic bands.

2020年度 報告書 （Web公開用）

作成者： DUTTAGUPTA SAMIK（東北大CSIS）

研究プロジェクト名： Charge and spin-dependent topologicaltransport phenomena in antiferromagnetic Weyl semi-metals
概要： The interplay of relativistic spin-orbit interaction, electronic band topology, and magnetic
order in antiferromagnetic Weyl semi-metals (WSMs) manifests in novel properties prospective for
antiferromagnetic spintronics. We aim to clarify the impact of topology on the magnetotransportproperties of antiferromagnetic WSM heterostructures. Our experimental result provides aconvenient approach for understanding of the manifestations of band topology in WSMs, crucial for
topological antiferromagnet spintronics.

We utilized C-plane (0001) and M-plane (1-100)
oriented MgO sub./under- layer/Mn3Sn (40nm)/MgO/Ru thin films patterned into Hall-bar
structures
fortheinvestigationofmagnetotransport properties. Previous studies
show a large anomalous Hall effect for M-planeorientations, while is zero for C-plane orientedstructures.
Planar Hall effect measurements
show a considerable anisotropic behavior
among C and M-plane orientations. Ourobservations reveal the signatures of chiralanomaly on the magnetotransport features in
antiferromagnetic WSM structures.

主要発表論文等:

Figure: (a), (b) Experimental results of planar Hall resistivity vsapplied angle of rotation of in-plane magnetic field for C-planeand M-plane Mn3Sn structures, respectively. The inset in (a)shows the schematic of the measurement configuration. IDC
refers to the applied current while VXY is the measured voltage.