Figure 4: Simulations of magnetization profiles of SrCu₂(BO₃)₂ as a function of inter- and intra-dimer interactions.

(a) Magnetization curves obtained from DMRG calculations on a 16 × 8 spin lattice with cylindrical boundary conditions for the singlet phase (J′/J=0.6; blue) and the plaquette phase (J′/J=0.7; red). Features move to lower H and new plateaus emerge as x increases from 0.6 to 0.7, echoing the experimental results. (b,c) Schematics of the spin superlattice configuration corresponding to the H_c1 and H_c3,c4 plateaus mapped onto a natural realization of the Shastry–Sutherland lattice, and computed using 16 × 8 and 8 × 8 spin lattices with open boundary conditions, respectively (b consists of two 16 × 8 and c consists of four 8 × 8 spin lattices). Solid lines denote orthogonal dimers, and the colour bar represents the magnitude of the local magnetization, where +m_z/−m_z indicate spins strongly polarized parallel/antiparallel to the field. The simulated superstructure opens the prospect of crystallization of ‘pinwheel’ triplet bound states in a square lattice at H_c1 and field-induced stripe ordering in the bound state of triplons at H_c3,c4.