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Title: Find a material with a continuous Neel to valence-bond-solid transition
Plain: Deconfined criticality has been seen mostly in computer models. The goal is a real magnet where the change from magnetic order to a pattern of spin singlets happens continuously or nearly so.
Precise: Identify a quasi-2D $S = 1/2$ magnet tunable by pressure, field or chemistry through a Neel to VBS (or plaquette) transition, and determine whether the transition is continuous with measured exponents or first order with a measured order-parameter jump. Candidates include SrCu2(BO3)2 under pressure and field. An answer is the material with the measured character of the transition.
Settled by: Neutron diffraction and NMR across the transition under pressure resolving both order parameters and any coexistence region.
Kind: well-posed
Answer type: identification
References: (empty)
Literature status: open
Status note: Cui et al. (Science 2023) reported a proximate deconfined critical point in SrCu2(BO3)2 with a weakly first-order transition.
Posed since: (empty)