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MA: Fachverband Magnetismus

MA 59: Posters Magnetism III

MA 59.24: Poster

Freitag, 20. März 2020, 09:00–12:00, P2/EG

Floquet Time Crystal in a Chiral Magnet — •Nina del Ser, Lukas Heinen, and Achim Rosch — Insitut für theoretische Physik, Universität zu Köln

We investigate how driving the conical phase of a chiral magnet with a time-periodic magnetic field can lead to the formation of Floquet time crystals: periodic perturbations of the steady-state magnetization in time as well as space. Our model is a 3D cubic spin lattice with Heisenberg and Dzyaloshinskii-Moriya interactions. We first obtain analytical expressions for the time-dependent magnetization of the steady state. We then expand around this time-dependent steady state using the Holstein-Primakoff formalism for bosonic excitations. Calculating the band spectrum requires the use of Floquet theory as it is a time-periodic problem. The Floquet band spectrum suggests the existence of unstable modes at certain resonant frequencies leading to the formations of new Floquet time crystal states, also observed in numerical experiments.