Lack of Self-affinity and Anomalous Roughening in Growth Processes

We contrast analytical results of a variety of growth models involving subdiffusion, thermal noise and quenched disorder with simulations of these models, concluding that the assumed self-affinity property is more an exception than a rule. In our two dimensional models, self-affine surfaces may only appear when the roughness exponent is $\chi = 1/2$ or $\chi = 1$. A new scaling picture, which leads to more suitable ways of determining the scaling exponents, is proposed when lack of self-affinity exists.