Exact ground states of a spin-1/2 Ising-Heisenberg model on the Shastry-Sutherland lattice in a magnetic field

Abstract

Exact ground states of a spin-1/2 Ising-Heisenberg model on the Shastry-Sutherland lattice with Heisenberg intra-dimer and Ising inter-dimer couplings are found by two independent rigorous procedures. The first method uses a unitary transformation to establish a mapping correspondence with an effective classical spin model, while the second method relies on the derivation of an effective hard-core boson model by continuous unitary transformations. Both methods lead to equivalent effective Hamiltonians providing a convincing proof that the spin-1/2 Ising-Heisenberg model on the Shastry-Sutherland lattice exhibits a zero-temperature magnetization curve with just two intermediate plateaus at one-third and one-half of the saturation magnetization, which correspond to stripe and checkerboard orderings of singlets and polarized triplets, respectively. The nature of the remarkable stripe order relevant to the one-third plateau is thoroughly investigated with the help of the corresponding exact eigenvector. The rigorous results for the spin-1/2 Ising-Heisenberg model on the Shastry-Sutherland lattice are compared with the analogous results for the purely classical Ising and fully quantum Heisenberg models. Finally, we discuss to what extent the critical fields of SrCu2(BO3)2 and (CuCl)Ca2Nb3O10 can be described within the suggested Ising-Heisenberg model.

15 pages, 6 figures, minor corrections

References in corpus (6)

• Fractional magnetization plateaus and magnetic order in the Shastry Sutherland magnet TmB4
• Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2
• Effective Theory of Magnetization Plateaux in the Shastry-Sutherland Lattice
• Effective models for gapped phases of strongly correlated quantum lattice models
• Exotic magnetisation plateaus in a quasi-2D Shastry-Sutherland model
• Unconventional magnetization plateaus in a Shastry-Sutherland spin tube

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• Fractional magnetization plateaux of a spin-1/2 Heisenberg model on the Shastry-Sutherland lattice: effect of quantum XY interdimer coupling
• Magnetization plateaus and bipartite entanglement of an exactly solved spin-1/2 Ising-Heisenberg orthogonal-dimer chain
• Detection of unbroken phase of non-Hermitian system via Hermitian factorization surface
• Theory of magnetism for rare-earth magnets on the Shastry-Sutherland lattice with non-Kramers ions
• Tree-Graph Based Construction of Quantum Spin Models with Exact Ground State