Frustrated quantum Heisenberg antiferromagnets at high magnetic fields: Beyond the flat-band scenario
Frustrated quantum Heisenberg antiferromagnets at high magnetic fields: Beyond the flat-band scenario
We consider the spin-1/2 antiferromagnetic Heisenberg model on three frustrated lattices (the diamond chain, the dimer-plaquette chain, and the two-dimensional square-kagome lattice) with almost dispersionless lowest magnon band. Eliminating high-energy degrees of freedom at high magnetic fields, we construct low-energy effective Hamiltonians, which are much simpler than the initial ones. …