Figure 1

Panels (a) and (b) show two different configurations satisfying the constraint of zero or one electron per site and one electron of arbitrary spin per triangle. The arrows indicate possible ring-hopping processes. An equivalent colored dimer representation on a honeycomb lattice is shown in (c) and (d); the colors encode particle spins. Ring exchanges conserve the parity of the number of dimers on the sublattice shown in panel (e). Panel (f) shows the 24-site cluster used for the exact diagonalization. The dimers are arranged to maximize the next-nearest-neighbor spin interaction along the dashed lines.Reuse & Permissions

Figure 2

Exact diagonalization of the two-color dimer model on an 18-site (left panels) and 24-site (right panels) honeycomb cluster. The upper panels show the GS energies of different $S_z$ sectors as a function of next-nearest-neighbor coupling $J/g$. The lower ones show the GS expectation values of the spin part of the Hamiltonian.Reuse & Permissions