Quantum Disordered State of Magnetic Charges in Nanoengineered Honeycomb Lattice

A quantum magnetic state due to magnetic charges is never observed, even though they are treated as quantum mechanical variables in theoretical calculations. Here, the occurrence of a novel quantum disordered state of magnetic charges in a nanoengineered magnetic honeycomb lattice of ultra‐small connecting elements is demonstrated. The experimental research, performed using spin resolved neutron scattering, reveals a massively degenerate ground state, comprised of low integer and energetically forbidden high integer magnetic charges, that manifests cooperative paramagnetism at low temperature. The system tends to preserve the degenerate configuration even under large magnetic field application. It exemplifies the robustness of disordered correlation of magnetic charges in a 2D honeycomb lattice. The realization of quantum disordered ground state elucidates the dominance of exchange energy, which is enabled due to the nanoscopic magnetic element size in nanoengineered honeycomb. Consequently, an archetypal platform is envisaged to study quantum mechanical phenomena due to emergent magnetic charges. A quantum disordered state of magnetic charges is a new concept, with magnetic properties analogous to spin liquid materials. This work shows striking evidence to the occurrence of this emergent phenomenon in a thermally tunable artificial permalloy honeycomb lattice. The figure manifests macroscopic degeneracy (Figure a) through the analysis of polarized neutron reflectivity (Figure b) at low temperature.