Distinct Optical Excitation Mechanisms of a Coherent Magnon in a van der Waals Antiferromagnet

Abstract

The control of antiferromagnets with ultrashort optical pulses has emerged as a prominent field of research. Tailored laser excitation can launch coherent spin waves at terahertz frequencies, yet a comprehensive description of their generation mechanisms is still lacking despite extensive efforts. Using terahertz emission spectroscopy, we investigate the generation of a coherent magnon mode in the van der Waals antiferromagnet NiPS${}_3$ under a range of photoexcitation conditions. By tuning the pump photon energy from transparency to resonant with a $d$-$d$ transition, we reveal a striking change in the coherent magnon's dependence on the pump polarization, indicating two distinct excitation mechanisms. Our findings provide a strategy for the manipulation of magnetic modes via photoexcitation around sub-gap electronic states.

arXiv comment17 pages, 16 figures

References in corpus (19)

• Antiferromagnetic spintronics
• Antiferromagnetic spintronics
• Antiferromagnetic opto-spintronics: Part of a collection of reviews on antiferromagnetic spintronics
• An effective magnetic field from optically driven phonons
• Spin Oscillations in Antiferromagnetic NiO Triggered by Circularly Polarized Light
• Light-driven ultrafast phonomagnetism
• Temporal and spectral fingerprints of ultrafast all-coherent spin switching
• Inverse magneto-refraction as a mechanism for laser modification of spin-spin exchange parameters and subsequent terahertz emission from iron oxides
• Polarizing an antiferromagnet by optical engineering of the crystal field
• Coherent spin-wave transport in an antiferromagnet
• Highly Anisotropic Excitons and Multiple Phonon Bound States in a Van der Waals Antiferromagnetic Insulator
• Spin-Induced Linear Polarization of Excitonic Emission in Antiferromagnetic van der Waals Crystals
• Controlling the anisotropy of a van der Waals antiferromagnet with light
• Ultrafast optical excitation of coherent magnons in antiferromagnetic NiO
• Exciton-driven antiferromagnetic metal in a correlated van der Waals insulator
• Spin wave Hamiltonian and anomalous scattering in NiPS${}_3$
• Dimensionality crossover to 2D vestigial nematicity from 3D zigzag antiferromagnetism in an XY-type honeycomb van der Waals magnet
• Ultrafast optical excitation of magnetic dynamics in van der Waals magnets: Coherent magnons and BKT dynamics in NiPS${}_3$
• Optical excitation of magnons in an easy-plane antiferromagnet: Application to Sr${}_2$IrO${}_4$

Cited by in corpus (3)

• Probing the band structure of the strongly correlated antiferromagnet NiPS3 across its phase transition
• Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3
• Optically induced magnetic inertia and magnons from non-Markovian extension of the Landau-Lifshitz-Gilbert equation