Effect of disorder and notches on crack roughness.

We analyze the effect of disorder and notches on crack roughness in two dimensions. Our simulation results based on large system sizes and extensive statistical sampling indicate that the crack surface exhibits a universal local roughness of zeta(loc)=0.71 and is independent of the initial notch size and disorder in breaking thresholds. The global roughness exponent scales as zeta=0.87 and is also independent of material disorder. Furthermore, we note that the statistical distribution of crack profile height fluctuations is also independent of material disorder and is described by a Gaussian distribution, albeit deviations are observed in the tails.