Nonlinear terahertz Néel spin-orbit torques in antiferromagnetic Mn${}_2$Au

Abstract

Antiferromagnets have large potential for ultrafast coherent switching of magnetic order with minimum heat dissipation. In novel materials such as Mn${}_2$Au and CuMnAs, electric rather than magnetic fields may control antiferromagnetic order by Néel spin-orbit torques (NSOTs), which have, however, not been observed on ultrafast time scales yet. Here, we excite Mn${}_2$Au thin films with phase-locked single-cycle terahertz electromagnetic pulses and monitor the spin response with femtosecond magneto-optic probes. We observe signals whose symmetry, dynamics, terahertz-field scaling and dependence on sample structure are fully consistent with a uniform in-plane antiferromagnetic magnon driven by field-like terahertz NSOTs with a torkance of (150$\pm$50) cm${}^2$/A s. At incident terahertz electric fields above 500 kV/cm, we find pronounced nonlinear dynamics with massive Néel-vector deflections by as much as 30°. Our data are in excellent agreement with a micromagnetic model which indicates that fully coherent Néel-vector switching by 90° within 1 ps is within close reach.

16 pages, 4 figures

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Cited by in corpus (14)

• Nonlinear terahertz Néel spin-orbit torques in antiferromagnetic Mn${}_2$Au
• Extreme Terahertz Magnon Multiplication Induced by Resonant Magnetic Pulse Pairs
• Switching of Magnetization in Quantum Antiferromagnets with Time-Dependent Control Fields
• Intrinsic Dynamic Generation of Spin Polarization by Time-Varying Electric Field
• Néel Spin-Orbit Torque in Antiferromagnetic Quantum Spin and Anomalous Hall Insulators
• Light-induced Orbital and Spin Magnetism in $3d$, $4d$, and $5d$ Transition Metals
• Exchange enhanced switching by alternating fields in quantum antiferromagnets
• Picosecond transfer from short-term to long-term memory in analog antiferromagnetic memory device
• Competition between terahertz magnetoelectric and Néel spin-orbit torque driven spin dynamics in metallic antiferromagnets
• Pulsed Magnetophononics in Gapped Quantum Magnets
• Landau-Lifshitz damping from Lindbladian dissipation in quantum magnets
• Switching magnetization of quantum antiferromagnets: Schwinger boson mean-field theory compared to exact diagonalization
• Giant Response and Harmonic Generation in Néel-Torque Antiferromagnetic Resonance
• Terahertz spin-orbit torque as a drive of spin dynamics in the insulating antiferromagnet Cr${}_2$O${}_3$