Real-Space Observation of Magnon Interaction with Driven Space-Time Crystals

The concept of Space-Time Crystals (STC), i.e. translational symmetry breaking in time and space, was recently proposed experimentally demonstrated for quantum systems. Here, we transfer this to magnons demonstrate a driven STC at room temperature. is realized by strong homogeneous micro-wave pumping micron-sized permalloy (Py) stripe directly imaged Scanning Transmission X-ray Microscopy (STXM). For fundamental understanding the formation STC, micromagnetic simulations are carefully adapted model experimental findings. Beyond mere generation observe magnonic band structure due back folding modes STC's Brillouin zone boundaries. We show interactions with that appear as lattice scattering. This results ultra short spin waves down 100 nm wavelength cannot be described classical dispersion relations linear wave excitations. expect temperature STCs will useful tool investigate non-linear physics, they can easily generated manipulated control their spatial temporal structure.