Two-dimensional magnetic monopole gas in an oxide heterostructure

Magnetic monopoles have been proposed as emergent quasiparticles in magnetically frustrated pyrochlore spin ice compounds, such as R₂Ti₂O₇ (RTO) (R = Ho, Dy). To date, all experimental investigations have been limited to the behaviour of large ensembles comprised of equal numbers of monopoles and antimonopoles in macroscopic bulk. Therefore, fundamental questions about the existence, properties, and dynamics of single, isolated monopoles, as well as the new phases of matter that these monopoles may form, remain unanswered or inaccessible. To address these issues, we propose the formation of a two-dimensional magnetic monopole gas (2DMG) with a net magnetic charge and whose monopole density can be controlled by an external field, at the interface between a spin ice and an isostructural antiferromagnetic (AFM) pyrochlore iridate (e.g. R₂Ir₂O₇ (RIO)). Our proposal is based on a series of Monte Carlo simulations of the thermodynamic and transport properties, which also demonstrate the robustness of the 2DMG against long-range dipolar interactions. This proposed 2DMG should enable entirely new classes of experiments and devices which can be performed on magnetic monopoles, akin to two-dimensional electron gases in semiconductor heterostructures.