Giant room temperature anomalous Hall effect and tunable topology in a ferromagnetic topological semimetal Co2MnAl

Peigang Li; Jahyun Koo; Wei Ning; Jinguo Li; Leixin Miao; Lujin Min; Yanglin Zhu; Yu Wang; Nasim Alem; Chao-Xing Liu; Zhiqiang Mao; Binghai Yan

doi:10.1038/s41467-020-17174-9

Giant room temperature anomalous Hall effect and tunable topology in a ferromagnetic topological semimetal Co₂MnAl

Nat Commun. 2020 Jul 10;11(1):3476. doi: 10.1038/s41467-020-17174-9.

Authors

Peigang Li^#¹, Jahyun Koo^#², Wei Ning³, Jinguo Li⁴, Leixin Miao⁵, Lujin Min^{6

5}, Yanglin Zhu^{1

6}, Yu Wang^{1

6}, Nasim Alem⁵, Chao-Xing Liu⁶, Zhiqiang Mao^{7

8}, Binghai Yan⁹

Affiliations

¹ Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, 70118, USA.
² Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel.
³ Department of Physics, Pennsylvania State University, University Park, State College, PA, 16802, USA. wvn5038@psu.edu.
⁴ Superalloys Division, Institute of Metal Reseach, Chinese Academy of Sciences, 110016, Shenyang, China.
⁵ Department of Materials Science and Engineering, Pennsylvania State University, University Park, State College, PA, 16802, USA.
⁶ Department of Physics, Pennsylvania State University, University Park, State College, PA, 16802, USA.
⁷ Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, 70118, USA. zim1@psu.edu.
⁸ Department of Physics, Pennsylvania State University, University Park, State College, PA, 16802, USA. zim1@psu.edu.
⁹ Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel. binghai.yan@weizmann.ac.il.

^# Contributed equally.

Abstract

Weyl semimetals exhibit unusual surface states and anomalous transport phenomena. It is hard to manipulate the band structure topology of specific Weyl materials. Topological transport phenomena usually appear at very low temperatures, which sets challenges for applications. In this work, we demonstrate the band topology modification via a weak magnetic field in a ferromagnetic Weyl semimetal candidate, Co₂MnAl, at room temperature. We observe a tunable, giant anomalous Hall effect (AHE) induced by the transition involving Weyl points and nodal rings. The AHE conductivity is as large as that of a 3D quantum AHE, with the Hall angle (Θ^H) reaching a record value ([Formula: see text]) at the room temperature among magnetic conductors. Furthermore, we propose a material recipe to generate large AHE by gaping nodal rings without requiring Weyl points. Our work reveals an intrinsically magnetic platform to explore the interplay between magnetic dynamics and topological physics for developing spintronic devices.

Grants and funding

ERC grant No. 815869/EC | EU Framework Programme for Research and Innovation H2020 | H2020 Priority Excellent Science | H2020 European Research Council (H2020 Excellent Science - European Research Council)