Properties of the +/- J Ising spin glass on the triangular lattice

We study the ground state of the +/-J Ising spin glass on the triangular la ttice with an arbitrary concentration p of negative bonds. In agreement wit h a previous study on the square lattice, it is found that the spin correla tion exponent eta remains constant over a range of defect concentration p(c 1) < p < p(c2). Furthermore, the value of eta obtained is 0.33 +/- 0.02 whi ch agrees, within error bars, with the square lattice result. This indicate s that the spin glass phases on the two lattices are in the same universali ty class. However, the model on the triangular lattice has an upper critica l concentration at p = p(c2) that is not present for the square lattice. Th is transition is found to be due to a percolation of frustrated plaquettes which drives a crossover to a frustrated antiferromagnetic phase. We show t hat this occurs at p(c2) = 0.8472 +/- 0.0001 with the usual percolation exp onents for two dimensions.