Monopole Traps for Position-Based Information Coding

Spin-ice materials have long served as a fertile ground for exploring emergent quasiparticles, most notably magnetic monopoles arising from their exotic excitations. The recently proposed two-dimensional magnetic monopole gases at spin-ice interfaces have opened new avenues for device functionalities. In this talk, I will present a spin-ice-based heterostructure capable of encoding magnetic monopole positions for non-volatile information storage applications. Our approach introduces a fragmented 3-in–1-out/1-in–3-out barrier layer within the spin-ice matrix, forming two stable monopole traps whose occupancy can be switched by an external magnetic field. Monte Carlo simulations demonstrate robust bistable switching, full reversibility, and thermal stability up to 0.22 K, highlighting the feasibility of repeatable memory operation. Notably, the heterostructure exhibits emergent ferromagnetism tied to monopole position, enabling non-destructive state readout through spatially resolved magnetic imaging. Unlike larger-scale topological carriers such as skyrmions, confined monopoles provide three orders of magnitude higher information density. These findings establish monopole-trap heterostructures as a scalable platform for ultra-compact, next-generation memory technologies.