FRUSTRATION-INDUCED NONLINEAR RESISTIVITIES OF HIGH-T(C) SUPERCONDUCTORS IN MAGNETIC-FIELDS

We have performed a finite-temperature (T) dynamic simulation to calculate transport properties of a two-dimensional (2D) frustrated Josephson-coupled lattice as a model of high-T(c) superconductors in magnetic fields (H/H(c2) much less than 1). In the weak-frustration region the I-V characteristics and magnetoresistance obey coexisting power laws with continuously varying exponents, V is-proportional-to I(alpha(T,H)) and V is-proportional-to H(beta(T,I)). These field-dependent nonlinear resistive behaviors are analogous to experimentally observed ones in single crystals of high-T(c) oxides, and they are ascribed to the frustration-induced unbinding mechanism of 2D vortex-antivortex pairs. A possible Kosterlitz-Thouless vortex-antivortex unbinding transition in magnetic fields is also addressed based on the temperature dependence of power-law exponents.