Evolution of magnetic structure driven by synthetic spin-orbit coupling in a two-component Bose-Hubbard model

We study the evolution of magnetic structures driven by a synthetic spin-orbit coupling in a one-dimensional two-component Bose-Hubbard model. In addition to the Mott insulator-superfluid transition, in the Mott insulator phases we found a transition from a gapped ferromagnetic phase to a gapless chiral phase by increasing the strength of the spin-orbit coupling. Further increasing the spin-orbit coupling drives a transition from the gapless chiral phase to a gapped antiferromagnetic phase. These magnetic structures persist in superfluid phases. In particular, in the chiral Mott insulator and chiral superfluid phases, incommensurability is observed in characteristic correlation functions. These unconventional Mott insulator phase and superfluid phase demonstrate the different effects arising from the competition between the kinetic energy and the spin-orbit coupling.