Noise and hysteresis in charged stripe, checkerboard, and clump forming systems

摘要

We numerically examine noise fluctuations and hysteresis phenomena in charged systems that form stripe, labyrinth or clump patterns. It is believed that charge inhomogeneities of this type arise in two-dimensional (2D) quantum hall systems and in electron crystal structures in high temperature superconductors, while related patterns appear in manganites and type-I superconductors. Recent noise and transport experiments in two-dimensional electron gases and high temperature superconducting samples revealed both 1/f~α noise signatures and hysteretic phenomena. Using numerical simulations we show that 1/f~α noise fluctuations and hysteresis are generic features that occur in charge systems which undergo a type of phase separation that results in stripes, clumps, checkerboards, or other inhomogeneous patterns. We find that these systems exhibit 1/f~α fluctuations with 1.2 < α < 1.8, rather than simple 1/f or 1/f~2 fluctuations. We also propose that the 2D metal insulator transition may be associated with a clump electron glass phase rather than a Wigner glass phase.