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MA: Fachverband Magnetismus
MA 36: Terahertz Spintronics II
MA 36.5: Talk
Thursday, March 21, 2024, 10:30–10:45, EB 202
Voltage-Controlled High-Bandwidth Terahertz Oscillators Based On Antiferromagnets — Mike Lund1, Davi Rodrigues2, Karin Everschor-Sitte3, and •Kjetil Hals1 — 1Department of Engineering Sciences, University of Agder, 4879 Grimstad, Norway — 2Department of Electrical and Information Engineering, Polytechnic University of Bari, 70125 Bari, Italy — 3Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
The terahertz (THz) technology gap refers to a frequency range of electromagnetic radiation in the THz regime where current technologies are inefficient for generating and detecting radiation. Here, we show that noncollinear antiferromagnets (NCAFM) with kagome structure host gapless self-oscillations whose frequencies are tunable from 0 Hz to the THz regime via electrically induced spin-orbit torques (SOTs) [1]. The auto-oscillations' initiation, bandwidth, and amplitude are investigated by deriving an effective theory, which captures the reactive and dissipative SOTs. We find that the dynamics strongly depends on the ground state's chirality, with one chirality having gapped excitations, whereas the opposite chirality provides gapless self-oscillations. Our results demonstrate that NCAFMs offer unique THz functional components, which could play a significant role in bridging the gap between technologies operating in the microwave and infrared regions.
[1] M. A. Lund, D. R. Rodrigues, K. Everschor-Sitte, and K. M. D. Hals, Phys. Rev. Lett. 131, 156704 (2023).
Keywords: Antiferromagnets; Self-oscillations; Voltage-controlled frequency generators; Spin-orbit torques