Random hopping among localized states and charge fluctuation at disordered surfaces

We show that 1/f noise of charge fluctuation at disordered surfaces follows naturally from random hopping of electrons among localized states. Computer models are proposed with hopping mechanisms simplified, and the occurrence of 1/f?? power spectrum is robust. The lifetime distribution of electrons is found to be D(??) = ??-?? and a connection between the lifetime distribution and the power spectrum is derived. It is shown that the 1/f noise comes from random superposition of oscillatory spectra. We also define an generalized random walk model to act as the underlying mechanism of 1/f noise in disordered systems.EI011-6