Monopole Current Control in Artificial Spin Ice via Localized Fields

Artificial spin ice systems are lattices of single-domain nanomagnets whose dipolar interactions produce geometric frustration and can support emergent magnetic monopole excitations. We demonstrate the control of monopole currents in square artificial spin ice by adding a row of control nanomagnets positioned perpendicular to the lattice plane above one edge. Monte Carlo simulations reveal that localized fields from these control elements can either suppress or promote monopole nucleation along the biased edge, steering monopole currents of chosen polarity across the lattice, sometimes even opposing the global in-plane field. These elements reshape the energy landscape, enabling tailored and guided state transitions. Our results offer a strategy for manipulating collective behaviors in artificial spin ice through localized fields. This approach holds promise for applications in magnetic memory, physical reservoir computing, reconfigurable magnetic logic, spin-based information processing, and device architectures requiring directional magnetic charge transport.