The effect of spin-orbit coupling on the effective-spin correlation in YbMgGaO4

Understand

Motivated by the recent experiments on the triangular lattice spin liquid YbMgGaO$_4$, we explore the effect of spin-orbit coupling on the effective-spin correlation of the Yb local moments.

• We point out the anisotropic interaction between the effective-spins on the nearest neighbor bonds is sufficient to reproduce the spin-wave dispersion of the fully polarized state in the presence of strong magnetic field normal to the triangular plane.
• We further evaluate the effective-spin correlation within the mean-field spherical approximation.
• We explicitly demonstrate that, the nearest-neighbor anisotropic effective-spin interaction, originating from the strong spin-orbit coupling, enhances the effective-spin correlation at the M points in the Brillouin zone.