Laser-driven quantum magnonics and THz dynamics of the order parameter in antiferromagnets

Abstract

The impulsive generation of two-magnon modes in antiferromagnets by femtosecond optical pulses, so-called femto-nanomagnons, leads to coherent longitudinal oscillations of the antiferromagnetic order parameter that cannot be described by a thermodynamic Landau-Lifshitz approach. We argue that this dynamics is triggered as a result of a laser-induced modification of the exchange interaction. In order to describe the oscillations we have formulated a quantum mechanical description in terms of magnon pair operators and coherent states. Such an approach allowed us to} derive an effective macroscopic equation of motion for the temporal evolution of the antiferromagnetic order parameter. An implication of the latter is that the photo-induced spin dynamics represents a macroscopic entanglement of pairs of magnons with femtosecond period and nanometer wavelength. By performing magneto-optical pump-probe experiments with 10 femtosecond resolution in the cubic KNiF${}_3$ and the uniaxial K${}_2$NiF${}_4$ collinear Heisenberg antiferromagnets, we observed coherent oscillations at the frequency of 22 THz and 16 THz, respectively. The detected frequencies as a function of the temperature ideally fit the two-magnon excitation up to the Néel point. The experimental signals are described as dynamics of magnetic linear dichroism due to longitudinal oscillations of the antiferromagnetic vector.

arXiv comment25 pages, 10 figures

References in corpus (16)

• The building blocks of magnonics
• Spin Oscillations in Antiferromagnetic NiO Triggered by Circularly Polarized Light
• Ultrafast and reversible control of the exchange interaction in Mott insulators
• Magnetic light scattering in low-dimensional quantum spin systems
• Inverse magneto-refraction as a mechanism for laser modification of spin-spin exchange parameters and subsequent terahertz emission from iron oxides
• Optical determination of the Neel vector in a CuMnAs thin-film antiferromagnet
• Macrospin Dynamics in Antiferromagnets Triggered by Sub-20 femtosecond Injection of Nanomagnons
• Magnon squeezing in an antiferromagnet: reducing the spin noise below the standard quantum limit
• Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates
• Effective Hamiltonians for fastly driven many-body lattice systems
• Experimental observation of the optical spin-orbit torque
• Manipulating magnetism by ultrafast control of the exchange interaction
• Frequency and wavenumber selective excitation of spin waves through coherent energy transfer from elastic waves
• Exponential and Laguerre Squeezed States for su(1,1) Algebra and Calogero-Sutherland Model
• Multiphoton communication in lossy channels with photon-number entangled states
• Ultrafast cooling and heating scenarios for the laser induced phase transition in CuO

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