Scaling determination of the nonlinear $I-V$ characteristics for two-dimensional superconducting networks

It is shown from computer simulations that the current-voltage $(I-V)$ characteristics for the two-dimensional XY model with resistively shunted Josephson junction dynamics and Monte Carlo dynamics obeys a finite-size scaling form from which the nonlinear $I-V$ exponent a can be determined to good precision. This determination supports the conclusion $a=z+1,$ where z is the dynamic critical exponent. The results are discussed in the light of the contrary conclusion reached by Tang and Chen [Phys. Rev. B 67, 024508 (2003)] and the possibility of a breakdown of scaling suggested by Bormann [Phys. Rev. Lett. 78, 4324 (1997)].