Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 40: Frustrated Magnets II
MA 40.10: Talk
Thursday, March 21, 2024, 17:30–17:45, H 1058
Electric field driven flat bands in S=1/2 sawtooth chain. — Johannes Richter1, 2, •Vadim Ohanyan3, 4, Jörg Schulenburg5, and Jürgen Schnack6 — 1Institut für Physik, Universität Magdeburg, P.O. Box 4120, D-39016 Magdeburg, Germany — 2Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, D-01187 Dresden, Germany — 3Laboratory of Theoretical Physics, Yerevan State University, 1 Alex Manoogian, 0025 Yerevan, Armenia — 4CANDLE, Synchrotron Radiation Institute, 31 Acharyan Street, 0040 Yerevan, Armenia — 5Universitätsrechenzentrum, Universität Magdeburg, D-39016 Magdeburg, Germany — 6Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
We consider one of the paradigmatic models of frustrated spin system, a S=1/2 sawtooth chain with magnetoelectric coupling, realized due to Katsura-Nagaosa-Baladsky (KNB) mechanism. While the magnetic field acts on the spin system via the ordinary Zeeman term, the coupling of an applied electric field with the spins given by the KNB mechanism is effectively realized as a Dzyaloshinskii-Moriya interaction. One can drive the spin system into a flat-band scenario by applying an appropriate electric field, thus overcoming the restriction of fine-tuned exchange couplings. Particularly, if the direction of the electric field coincides with the basal line of the chain, the value of the saturation magnetic field can be reduced. We find a magnetization jump driven by the electric field as well as a jump of the electric polarization driven by the magnetic field, the system exhibits a strong magnetoelectric effect and an enhanced electrocaloric effect.
Keywords: Sawtooth chain; localized magnons; magnetoelectric effect; Katsura-Nagaosa-Balatsky mechanism; Electrocaloric effect