Spin-gap effect on resistivity in the t-J model

We calculate the spin-gap effect on de resistivity in the t-J model of high -T-c cuprates by using the Ginzburg-Landau theory coupled with a gauge fiel d as its effective field theory to obtain rho (T) proportional to T{1- c (T * - T)(d)}, where T* is the spin-gap onset temperature. By taking the compa ctness of the massive gauge field into account, the exponent d deviates fro m its mean-field value 1/2 and becomes a nonuniversal T-dependent quantity, which improves the correspondence with the experiments.