Dichotomous dynamics of magnetic monopole fluids

How magnetic monopole currents traverse spin-ice materials has proven notoriously difficult to understand. Recently, it was discovered that emergent dynamical fractal trajectories underpin the monopole motion. Applying these novel concepts to field-driven magnetic monopole currents predicts a characteristic dichotomy in both their DC and AC dynamics. Experimental investigations using monopole current spectroscopy then reveal a strong dichotomy in the monopole current response to applied DC and AC magnetic fields and in monopole noise. An accurate atomic-scale understanding of the mechanisms of magnetic monopole currents in spin ice is thereby established. They are constrained by the geometry of allowed fractal trajectories subject to specific spin-configuration termini to monopole motion. Such self-generated dynamical heterogeneity represents a paradigm in quantum magnetic transport.