Topological disorder and conductance fluctuations in thin films.

Abstract

1/f noise in certain amorphous and polycrystalline materials may have an origin in the intrinsic disorder in these systems. Modeling such systems as topologically disordered linear networks reveals how the range and scale of the dynamical current redistribution due to isolated fluctuators depend on the network's degree of disorder. We introduce a ``disorder parameter'' \ensuremath{\xi}, which quantifies the degree of topological disorder in simulated resistor networks. The magnitude of conductance fluctuations in the networks caused by removal of single resistors is found to scale with \ensuremath{\xi}. Such bond breaking events are analogous to the motion of diffusing defects in materials such as hydrogenated amorphous silicon (a-Si:H). These results extended to the scenario of multiple simultaneous bond breaking events suggest how fluctuations on all scales might occur especially in disordered systems. \textcopyright{}1996 The American Physical Society.