Spin-half Heisenberg antiferromagnet on two archimedian lattices: From the bounce lattice to the maple-leaf lattice and beyond

Article

关键词: SHASTRY-SUTHERLAND MODEL;    GROUND-STATE;    MAGNETIZATION PLATEAUS;    SQUARE LATTICE;    NEEL ORDER;    QUANTUM ANTIFERROMAGNETS;    PHASE-TRANSITIONS;    EXACT SPECTRA;    SIMULATIONS;    DISORDER;   

DOI  :  10.1103/PhysRevB.84.104406

来源: SCIE

【 摘 要 】

We investigate the ground state of the two-dimensional Heisenberg antiferromagnet on two Archimedean lattices, namely, the maple-leaf and bounce lattices as well as a generalized J-J' model interpolating between both systems by varying J'/J from J'/J = 0 (bounce limit) to J'/J = 1 (maple-leaf limit) and beyond. We use the coupled cluster method to high orders of approximation and also exact diagonalization of finite-sized lattices to discuss the ground-state magnetic long-range order based on data for the ground-state energy, the magnetic order parameter, the spin-spin correlation functions as well as the pitch angle between neighboring spins. Our results indicate that the pure bounce (J'/J = 0) and maple-leaf (J'/J = 1) Heisenberg antiferromagnets are magnetically ordered, however, with a sublattice magnetization drastically reduced by frustration and quantum fluctuations. We found that magnetic long-range order is present in a wide parameter range 0 <= J'/J'J less than or similar to J'(c)/J and that the magnetic order parameter varies only weakly with J'/J. At J'(c) approximate to 1.45J, a transition to a quantum orthogonal-dimer singlet ground state without magnetic long-range order takes place that is probably of first-order type, although we cannot rule out that this transition is second order. The orthogonal-dimer state is the exact ground state in this large-J' regime, and so our model has similarities to the Shastry-Sutherland model. Finally, we use the exact diagonalization to investigate the magnetization curve. We find a 1/3 magnetization plateau for J'/J' greater than or similar to 1.07 and another one at 2/3 of saturation emerging only at large J'/J greater than or similar to 3.

【 授权许可】

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