Magnon hydrodynamics in an atomically thin ferromagnet
Strong interactions between particles can lead to emergent collective excitations. Spin waves, known as magnons, have been predicted to reach a strongly interacting hydrodynamic regime, where they form a slow collective density mode. In this work, we isolate exfoliated sheets of chromium trichloride (CrCl 3 ), where magnon interactions are strong, and develop a technique to measure the collective magnon dynamics though nearby nitrogen-vacancy centers in diamond. Thermal magnetic fluctuations generated by monolayer CrCl 3 increase upon decreasing temperature; this anomalous trend may be a consequence of the damping rate of a low-energy magnon sound mode that sharpens as magnon interactions increase with increasing temperature. By measuring the magnetic fluctuations emitted by thin multilayer CrCl 3 in the presence of a variable-frequency drive field, we obtain spectroscopic evidence for this two-dimensional magnon sound mode.
Authors
- Li-Qiao Xia (ORCID: https://orcid.org/0000-0002-4267-763X)
- Amir Yacoby (ORCID: https://orcid.org/0000-0002-5737-7963)
- Pablo Jarillo‐Herrero (ORCID: https://orcid.org/0000-0001-8217-8213)
- Nikola Maksimovic (ORCID: https://orcid.org/0000-0002-4540-6579)
- Ruolan Xue
- Dahlia Klein (ORCID: https://orcid.org/0000-0001-9581-2105)
- Pavel E. Dolgirev (ORCID: https://orcid.org/0000-0003-4778-8694)
- Ryota Kitagawa (ORCID: https://orcid.org/0000-0002-8391-6019)
- Eugene Demler
- Francisco Machado (ORCID: https://orcid.org/0000-0003-0068-5073)
- David MacNeill
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- Aaron Müller (ORCID: https://orcid.org/0000-0002-5148-9235)
- Mikhail D. Lukin (ORCID: https://orcid.org/0000-0002-8658-1007)
Institutions
- Tokyo Institute of Technology (JP)
- Harvard University (US)
- National Institute for Materials Science (JP)
- Board of the Swiss Federal Institutes of Technology (CH)
- Center for Astrophysics Harvard & Smithsonian (US)
- Weizmann Institute of Science (IL)
- Massachusetts Institute of Technology (US)
Publication Details
- Journal
- Science
- Published
- 2026-05-21
- DOI
- https://doi.org/10.1126/science.adp2397
- Primary Topic
- Magnetic properties of thin films
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Gordon and Betty Moore Foundation
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Intelligence Community Postdoctoral Research Fellowship Program
- Office of Naval Research
- Army Research Office