New Exponent for the NonlinearIVCharacteristics of a Two Dimensional Superconductor

The exponent $a$ for the nonlinear $\mathrm{IV}$ characteristics, $V\sim I^a$, is obtained from a critical scaling argument for a two dimensional superconductor below $T_c$. The scaling assumption is supported by numerical simulations. The $\mathrm{IV}$ characteristics for the resistively shunted-juction model is simulated numerically, and excellent agreement with the predicted exponent is found. The new scaling exponent differs from the generally accepted Ambegaokar-Halperin-Nelson-Siggia result. The reason for this discrepancy is discussed.