Spin disorder and spin defects for novel photonics using two-dimensional magnets

The study of two-dimensional (2D) magnets is still in its infancy and we are on the continuous lookout for novel features for tuning their functional properties relevant for spin-photonic interfaces. The functionality of a 2D magnet stringently relies on the ability tune its excitons; their brightness, coherence, symmetries and energies. Spin disorder is an exclusive tuning knob available for photonic applications of 2D magnets, absent from the non-magnetic transition metal dichalcogenides (TMDs) or hexagonal boron nitride (hBN). We show using our recently developed high-fidelity many-body theoretical approach that the suppression of exciton brightness due to magnetic disordering is a principle that is valid across all variants of 2D magnets and can be explained unambiguously within our theoretical framework. Further, we show that the spin defects in 2D magnets can be used to produce narrow defect bound excitons with wavefunction symmetries and dimensionalities significantly different from its host material (without defects), promising novel photonic applications.