  Light-induced spin-orbit coupling is a flexible tool to study quantum
magnetism with ultracold atoms. In this work we show that spin-orbit coupled
Bose gases in a one-dimensional optical lattice can be mapped into a two-leg
triangular ladder with staggered flux following a lowest-band truncation of the
Hamiltonian. The effective flux and the ratio of the tunneling strengths can be
independently adjusted to a wide range of values. We identify a certain regime
of parameters where a hard-core boson approximation holds and the system
realizes a frustrated triangular spin ladder with tunable flux. We study the
properties of the effective spin Hamiltonian using the density-matrix
renormalization-group method and determine the phase diagram at half-filling.
It displays two phases: a uniform superfluid and a bond-ordered insulator. The
latter can be stabilized only for low Raman detuning. Finally, we provide
experimentally feasible trajectories across the parameter space of the SOC
system that cross the predicted phase transition.
