Strain engineering of the magnetic multipole moments and anomalous Hall effect in pyrochlore iridate thin films

Woo Jin Kim; Taekoo Oh; Jeongkeun Song; Eun Kyo Ko; Yangyang Li; Junsik Mun; Bongju Kim; Jaeseok Son; Zhuo Yang; Yoshimitsu Kohama; Miyoung Kim; Bohm-Jung Yang; Tae Won Noh

doi:10.1126/sciadv.abb1539

Strain engineering of the magnetic multipole moments and anomalous Hall effect in pyrochlore iridate thin films

Sci Adv. 2020 Jul 15;6(29):eabb1539. doi: 10.1126/sciadv.abb1539. eCollection 2020 Jul.

Authors

Woo Jin Kim^{1

2}, Taekoo Oh^{1

2

3}, Jeongkeun Song^{1

2}, Eun Kyo Ko^{1

2}, Yangyang Li^{1

2}, Junsik Mun⁴, Bongju Kim^{1

2}, Jaeseok Son^{1

2}, Zhuo Yang⁵, Yoshimitsu Kohama⁵, Miyoung Kim⁴, Bohm-Jung Yang^{1

2

3}, Tae Won Noh^{1

2}

Affiliations

¹ Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Republic of Korea.
² Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea.
³ Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Republic of Korea.
⁴ Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea.
⁵ Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.

Abstract

The recent observation of the anomalous Hall effect (AHE) without notable magnetization in antiferromagnets has suggested that ferromagnetic ordering is not a necessary condition. Thus, recent theoretical studies have proposed that higher-rank magnetic multipoles formed by clusters of spins (cluster multipoles) can generate the AHE without magnetization. Despite such an intriguing proposal, controlling the unconventional AHE by inducing these cluster multipoles has not been investigated. Here, we demonstrate that strain can manipulate the hidden Berry curvature effect by inducing the higher-rank cluster multipoles in spin-orbit-coupled antiferromagnets. Observing the large AHE on fully strained antiferromagnetic Nd₂Ir₂O₇ thin films, we prove that strain-induced cluster T ₁-octupoles are the only source of observed AHE. Our results provide a previously unidentified pathway for generating the unconventional AHE via strain-induced magnetic structures and establish a platform for exploring undiscovered topological phenomena via strain in correlated materials.

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).