Flicker noise in thin lipid films

Nonlinear charge conduction in an organized assembly of lipid molecules has long been established. However, the exact mechanism of charge transport across them is still not very clear. Since resistance involves the second moment of the current distribution, while noise involves the fourth moment, the noise measurement should be more informative about the underlying mechanism of charge transport. Using this perspective, we have measured noise in thin solid films of lipid molecules over a wide range of voltages that covers linear as well as nonlinear regimes. The power spectra obtained in this system show an increase in the relative noise with bias. This can be explained by considering the system to be a random resistor network consisting of nonlinear current elements.