Non-trivial fixed-point structure of the two-dimensional ±J 3-state Potts ferromagnet/spin glass

The fixed-point structure of the 2D 3-state random-bond Potts model with a bimodal (±J) distribution of couplings is fully determined using numerical renormalization group techniques. Along the paramagnet-to-ferromagnet critical line we find a total of four distinct fixed points: i) the pure critical fixed point, ii) the critical fixed point for the random-bond, but unfrustrated, ferromagnet, iii) a bicritical fixed point analogous to the bicritical Nishimori fixed point found in the random-bond frustrated Ising model, and iv) the zero-temperature spin-glass–to–ferromagnet critical fixed point. Estimates of the associated critical exponents are given for the various fixed points.