Spin-mediated shear oscillators in a van der Waals antiferromagnet

Alfred Zong; Qi Zhang; Faran Zhou; Yifan Su; Kyle Hwangbo; Xiaozhe Shen; Qianni Jiang; Haihua Liu; Thomas E Gage; Donald A Walko; Michael E Kozina; Duan Luo; Alexander H Reid; Jie Yang; Suji Park; Saul H Lapidus; Jiun-Haw Chu; Ilke Arslan; Xijie Wang; Di Xiao; Xiaodong Xu; Nuh Gedik; Haidan Wen

doi:10.1038/s41586-023-06279-y

Spin-mediated shear oscillators in a van der Waals antiferromagnet

Nature. 2023 Aug;620(7976):988-993. doi: 10.1038/s41586-023-06279-y. Epub 2023 Aug 2.

Authors

Alfred Zong^#^{1

2}, Qi Zhang^#^{3

4

5}, Faran Zhou^#⁴, Yifan Su², Kyle Hwangbo³, Xiaozhe Shen⁶, Qianni Jiang³, Haihua Liu⁷, Thomas E Gage⁷, Donald A Walko⁴, Michael E Kozina⁶, Duan Luo⁶, Alexander H Reid⁶, Jie Yang⁶, Suji Park^{6

8

9}, Saul H Lapidus⁴, Jiun-Haw Chu³, Ilke Arslan⁷, Xijie Wang⁶, Di Xiao^{3

10

11}, Xiaodong Xu^{12

13}, Nuh Gedik¹⁴, Haidan Wen^{15

16}

Affiliations

¹ Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
² Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
³ Department of Physics, University of Washington, Seattle, WA, USA.
⁴ Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA.
⁵ Department of Physics, Nanjing University, Nanjing, China.
⁶ SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁷ Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, USA.
⁸ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
⁹ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, USA.
¹⁰ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
¹¹ Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
¹² Department of Physics, University of Washington, Seattle, WA, USA. xuxd@uw.edu.
¹³ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. xuxd@uw.edu.
¹⁴ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. gedik@mit.edu.
¹⁵ Advanced Photon Source, Argonne National Laboratory, Lemont, IL, USA. wen@anl.gov.
¹⁶ Materials Science Division, Argonne National Laboratory, Lemont, IL, USA. wen@anl.gov.

^# Contributed equally.

PMID: 37532936
DOI: 10.1038/s41586-023-06279-y

Abstract

Understanding how microscopic spin configuration gives rise to exotic properties at the macroscopic length scale has long been pursued in magnetic materials^1-5. One seminal example is the Einstein-de Haas effect in ferromagnets^1,6,7, in which angular momentum of spins can be converted into mechanical rotation of an entire object. However, for antiferromagnets without net magnetic moment, how spin ordering couples to macroscopic movement remains elusive. Here we observed a seesaw-like rotation of reciprocal lattice peaks of an antiferromagnetic nanolayer film, whose gigahertz structural resonance exhibits more than an order-of-magnitude amplification after cooling below the Néel temperature. Using a suite of ultrafast diffraction and microscopy techniques, we directly visualize this spin-driven rotation in reciprocal space at the nanoscale. This motion corresponds to interlayer shear in real space, in which individual micro-patches of the film behave as coherent oscillators that are phase-locked and shear along the same in-plane axis. Using time-resolved optical polarimetry, we further show that the enhanced mechanical response strongly correlates with ultrafast demagnetization, which releases elastic energy stored in local strain gradients to drive the oscillators. Our work not only offers the first microscopic view of spin-mediated mechanical motion of an antiferromagnet but it also identifies a new route towards realizing high-frequency resonators^8,9 up to the millimetre band, so the capability of controlling magnetic states on the ultrafast timescale^10-13 can be readily transferred to engineering the mechanical properties of nanodevices.