Anomalous magnetoresistance by breaking ice rule in Bi₂Ir₂O₇/Dy₂Ti₂O₇ heterostructure

While geometrically frustrated quantum magnets host rich exotic spin states with potentials for revolutionary quantum technologies, most of them are necessarily good insulators which are difficult to be integrated with modern electrical circuit. The grand challenge is to electrically detect the emergent fluctuations and excitations by introducing charge carriers that interact with the localized spins without destroying their collective spin states. Here, we show that, by designing a Bi₂Ir₂O₇/Dy₂Ti₂O₇ heterostructure, the breaking of the spin-ice rule in insulating Dy₂Ti₂O₇ leads to a charge response in the conducting Bi₂Ir₂O₇ measured as anomalous magnetoresistance during the field-induced Kagome ice-to-saturated ice transition. The magnetoresistive anomaly also captures the characteristic angular and temperature dependence of this ice-rule-breaking transition, which has been understood as magnetic monopole condensation. These results demonstrate a novel heteroepitaxial approach for electronically probing the transition between exotic insulating spin states, laying out a blueprint for the metallization of frustrated quantum magnets.