Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet

Abstract

Two-dimensional (2D) magnetism has been long sought-after and only very recently realized in atomic crystals of magnetic van der Waals materials. So far, a comprehensive understanding of the magnetic excitations in such 2D magnets remains missing. Here we report polarized micro-Raman spectroscopy studies on a 2D honeycomb ferromagnet CrI3. We show the definitive evidence of two sets of zero-momentum spin waves at frequencies of 2.28 terahertz (THz) and 3.75 THz, respectively, that are three orders of magnitude higher than those of conventional ferromagnets. By tracking the thickness dependence of both spin waves, we reveal that both are surface spin waves with lifetimes an order of magnitude longer than their temporal periods. Our results of two branches of high-frequency, long-lived surface spin waves in 2D CrI3 demonstrate intriguing spin dynamics and intricate interplay with fluctuations in the 2D limit, thus opening up opportunities for ultrafast spintronics incorporating 2D magnets.

arXiv comment25 pages, 4 figures + 8 supplementary figures

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Cited by in corpus (55)

• Direct photoluminescence probing of ferromagnetism in monolayer two-dimensional CrBr3
• Evidence for a single-layer van der Waals multiferroic
• Evolution of interlayer and intralayer magnetism in three atomically thin chromium trihalides
• Fundamental Spin Interactions Underlying the Magnetic Anisotropy in the Kitaev Ferromagnet CrI${}_3$
• Direct observation of 2D magnons in atomically thin CrI${}_3$
• Antiferromagnetic ordering in van der Waals two-dimensional magnetic material MnPS3 probed by Raman spectroscopy
• Magnetic Two-Dimensional Chromium Trihalides: A Theoretical Perspective
• Gate-tunable spin waves in antiferromagnetic atomic bilayers
• Tuning Inelastic Light Scattering via Symmetry Control in 2D Magnet CrI${}_3$
• Twist engineering of the two-dimensional magnetism in double bilayer chromium triiodide homostructures
• Observation of Magnetic Proximity Effect Using Resonant Optical Spectroscopy of an Electrically Tunable MoSe${}_2$/CrBr${}_3$ Heterostructure
• Quasi-Two-Dimensional Magnon Identification in Antiferromagnetic FePS3 via Magneto-Raman Spectroscopy
• Distinct magneto-Raman signatures of spin-flip phase transitions in CrI3
• Magnetic field-induced quantum phase transitions in a van der Waals magnet
• Collective Excitations in 2D Materials
• Evidence of Noncollinear Spin Texture in Magnetic Moiré Superlattices
• Magnetic order induced polarization anomaly of Raman scattering in 2D magnet CrI${}_3$
• Topological magnonics in the two-dimensional van der Waals magnet CrI3
• Observation of the polaronic character of excitons in a two-dimensional semiconducting magnet $\mathrm{Cr}{\mathrm{I}}_3$
• Spin Dynamics in van der Waals Magnetic Systems
• Quantum rescaling, domain metastability and hybrid domain-walls in two-dimensional CrI3 magnets
• Electronic structure and magnetic properties of few-layer Cr${}_2$Ge${}_2$Te${}_6$: the key role of nonlocal electron-electron interaction effects
• Coherent Helicity-Dependent Spin-Phonon Oscillations in the Ferromagnetic van der Waals Crystal CrI3
• Tunable layered-magnetism-assisted magneto-Raman effect in a two-dimensional magnet $\mathrm{Cr}{\mathrm{I}}_3$
• Observation of stacking engineered magnetic phase transitions within moiré supercells of twisted van der Waals magnets
• Magneto-memristive switching in a two-dimensional layer antiferromagnet
• Layer Dependence of Stacking Order in Nonencapsulated Few-layer CrI3
• Magnon-phonon interactions enhance the gap at the Dirac point in the spin-wave spectra of CrI${}_3$ two-dimensional magnets
• Structural Monoclinicity and Its Coupling to Layered Magnetism in Few-Layer $\mathrm{Cr}{\mathrm{I}}_3$
• Thickness dependence of antiferromagnetic phase transition in Heisenberg-type MnPS3
• Magnon magic angles and tunable Hall conductivity in 2D twisted ferromagnetic bilayers
• Stacking-dependent topological magnons in bilayer CrI${}_3$
• Topological Valley Transport of Gapped Dirac Magnons in Bilayer Ferromagnetic Insulators
• Unconventional magnon excitation by off-resonant microwaves
• Tunable magnon topology in monolayer CrI${}_3$ under external stimuli
• Magnetic order in the computational 2D materials database (C2DB) from high throughput spin spiral calculations
• Insights on magnon topology and valley-polarization in 2D bilayer quantum magnets
• Roadmap on Quantum Magnetic Materials
• A new class of nonreciprocal spin waves on the edges of 2D antiferromagnetic honeycomb nanoribbons
• Computational methods for 2D materials modelling
• Controlling magnetism through Ising superconductivity in magnetic van der Waals heterostructures
• Valley-polarized domain wall magnons in 2D ferromagnetic bilayers
• Resonant Raman Scattering of Few Layers CrBr${}_3$
• Terahertz Magnetic and Lattice Excitations in van der Waals Ferromagnet VI3
• Electrical tuning of the magnetic properties of 2D magnets: the case of ${\mathrm{Cr}}_2{\mathrm{Ge}}_2{\mathrm{Te}}_6$
• Anomalous Tunneling Magnetoresistance Oscillation and Electrically Tunable Tunneling Anisotropic Magnetoresistance in Few-layer CrPS4
• Tailoring High-Frequency Magnonics in Monolayer Chromium Trihalides
• Theoretical realization of rich magnon topology by symmetry-breaking in honeycomb bilayer ferromagnets
• Asymmetric dynamics of edge exchange spin waves in honeycomb nanoribbons with zigzag and bearded edges boundaries
• Discretized dynamics of exchange spin wave bulk and edge modes in honeycomb nanoribbons with armchair edge boundaries
• Linear scaling relationship of Néel temperature and dominant magnons in pyrochlore ruthenates
• Magnon-polaron formation in XXZ quantum Heisenberg chains
• Symmetry analysis of cross-circular and parallel-circular Raman optical activity
• Laser-Irradiated CrI${}_3$: When Chiral Photons Meet Topological Magnons
• Van der Waals Antiferromagnets: From Early Discoveries to Future Directions in the 2D Limit