Fractional magnetization plateaux of a spin-1/2 Heisenberg model on the Shastry-Sutherland lattice: Effect of quantum XY interdimer coupling

Spin-1/2 Heisenberg model on the Shastry-Sutherland lattice is considered within the many-body perturbation theory developed from the exactly solved spin-1/2 Ising-Heisenberg model with the Heisenberg intradimer and Ising interdimer interactions. The former model is widely used for a description of magnetic properties of the layered compound SrCu2(BO3)(2), which exhibits a series of fractional magnetization plateaux at sufficiently low temperatures. Using the novel type of many-body perturbation theory we have found the effective model of interacting triplet excitations with the extended hardcore repulsion, which accurately recovers 1/8, 1/6 and 1/4 magnetization plateaux for moderate values of the interdimer coupling. A possible existence of a striking quantum phase of bound triplons is also revealed at low enough magnetic fields.

Automated summary

This study uses a novel type of many-body perturbation theory to investigate the Spin-1/2 Heisenberg model on the Shastry-Sutherland lattice. The study reveals the occurrence of specific magnetization plateaux and a possible quantum phase of bound triplons for moderate values of the interdimer coupling.