Magnetic properties of the doped Shastry-Sutherland (SS) model were calculated and compared to the measurements on the spin-liquid SrCu_(2-x)Mg_x(BO_3)_2 compound. We employed a new variational algorithm with a single quenched magnetic vacancy on an infinite SS lattice to determine the size and the shape of the spin polaron surrounding the impurity site. Due to a particular symmetry of the SS lattice, the spin polaron is extremely anisotropic with a short spatial extent.
COBISS.SI-ID: 1961060
We show that temperature and magnetic-field properties of the entanglement between spins on the two-dimensional Shastry-Sutherland lattice can be qualitatively described by analytical results for a qubit tetramer. Exact diagonalization of clusters with up to 20 sites reveals that the regime of fully entangled neighboring pairs coincides with the regime of finite spin gap in the spectrum. Additionally, the results for the regime of vanishing spin gap are discussed and related to the Heisenberg limit of the model.
COBISS.SI-ID: 1989220
The ESR measurements has been performed on alpha-NaMnO_2 polycrystalline sample, a quantum spin system on a frustrated 2D triangular lattice with spatially anisotropic Heisenberg exchange. From the susceptibility curve, we have determined the nearest-neighbor antiferromagnetic exchange coupling constants (in the preferably coupled spin chains, J1=65 K, and perpendicular to them, J2/J1=0.44) by employing the finite-temperature Lanczos method. The dominant magnetic anisotropy term of the single-ion type, D=-4.1 K, which establishes an easy-axis direction, is evaluated from the ESR linewidth.
COBISS.SI-ID: 21404967