Quasi-Particle density of states of disordered d-wave superconductors
  We present a numerical study of the quasi-particle density of states   (DoS) of two-dimensional d-wave superconductors in the presence of   smooth disorder. We find power law scaling of the DoS with an   exponent depending on the strength of the disorder and the   superconducting order parameter in quantitative agreement with the   theory of Nersesyan et al. (Phys.Rev.Lett. 72,   2628 (1994)). For strong disorder a transition to a constant DoS   occurs. Our results are in contrast to the case of short-ranged   disorder. 
Bodo Huckestein and Alexander Altland