Direct Observation and Analysis of Low-Energy Magnons with Raman Spectroscopy in Atomically Thin NiPS3

Woongki Na, Pyeongjae Park, Siwon Oh, Junghyun Kim, Allen Scheie, David Alan Tennant, Hyun Cheol Lee, Je Geun Park, Hyeonsik Cheong

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

van der Waals (vdW) magnets have rapidly emerged as a fertile playground for fundamental physics and exciting applications. Despite the impressive developments over the past few years, technical limitations pose a severe challenge to many other potential breakthroughs. High on the list is the lack of suitable experimental tools for studying spin dynamics on atomically thin samples. Here, Raman scattering techniques are employed to directly observe the low-lying magnon (∼1 meV) even in bilayer NiPS3. The advantage is that it offers excellent energy resolutions far better on low-energy sides than most inelastic neutron spectrometers can offer. More importantly, with appropriate theoretical analysis, the polarization dependence of the Raman scattering by those low-lying magnons also provides otherwise hidden information on the dominant spin-exchange scattering paths for different magnons. By comparing with high-resolution inelastic neutron scattering data, these low-energy Raman modes are confirmed to be indeed of magnon origin. Because of the different scattering mechanisms involved in inelastic neutron and Raman scattering, this information is fundamental in pinning down the final spin Hamiltonian. This work demonstrates the capability of Raman spectroscopy to probe the genuine two-dimensional spin dynamics in atomically thin vdW magnets, which can provide insights that are obscured in bulk spin dynamics.

Original languageEnglish
Pages (from-to)20482-20492
Number of pages11
JournalACS Nano
Volume18
Issue number31
DOIs
StatePublished - Aug 6 2024

Keywords

  • NiPS
  • Raman scattering
  • inelastic neutron scattering
  • magnon
  • van der Waals antiferromagnet

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