Orderings and renormalization-group flows of a stacked frustrated triangular system in three dimensions

Two distinct partially ordered phases have been revealed by the Landau-Ginzburg-Wilson and Monte Carlo studies of the stacked frustrated triangular Ising model. These two types of order, occurring consecutively as temperature is lowered, and an observed shifting between equivalent ordered phases at a given temperature can be explained by a physical interpretation of the expected global renormalization-group flows in temperature and sixfold symmetry-breaking field acting on the two-component order parameter. New Monte Carlo data are presented, which confirm long-range order and a previous prediction of the above interpretation. The transition from the paramagnetic phase is in the XY universality class, whereas the transition between the ordered phases appears to be a sixfold symmetry-breaking flop.