- Letter
Observation of dipole gap solitons and coherent phase modulation of magnetostatic surface spin waves
Phys. Rev. Materials 10, L091403 – Published 8 September, 2026
DOI: https://doi.org/10.1103/qwys-9xy9
Abstract
Soliton states of magnetostatic surface spin waves (MSSWs) hold great potential for nonlinear magnonics, yet their experimental existence remains elusive due to the difficulty in distinguishing them from other coherent states with phase modulations. Here, using phase- and spatiotemporal-resolved Brillouin light scattering spectroscopy, we resolve the phase evolution of MSSWs and identify two distinct nonlinear coherent phases: a dipole gap bright soliton under short-pulse excitation, evidenced by its characteristic phase plateau, and a coherent phase modulation under long-pulse excitation, exhibiting spatiotemporal periodicities—with nearly equal temporal periods in intensity and phase, and a spatial period in intensity linked to the temporal period via the group velocity. This coherent phase modulation originates from the four-magnon scattering, producing a tunable frequency-comb spectrum and displaying power-controlled nonreciprocity. Our work provides phase-resolved verification of MSSW solitons, reveals a coherent phase modulation, and establishes a multidimensional diagnostic framework for controlling nonlinear coherent phases in magnonics.
