Field-Induced Spin Nematic Phase of a Magnet on the Shastry-Sutherland Lattice with the Anisotropic Ferromagnetic Interaction

A spin-1/2 magnetic system with the ferromagnetic and antiferromagnetic interactions on the Shastry-Sutherland lattice is investigated using the numerical diagonalization of finite-size clusters. The easy-axis anisotropy is introduced at the ferromagnetic bond of the present system and the magnetization process in the external magnetic field parallel to the axis is studied. As a result, the field-induced two-magnon bound phase is found at higher magnetization region than half the saturation. Base on the analogy to the previous study on the spin ladder system, the spin nematic order perpendicular to the external field would be expected to appear in this two-magnon bound phase.