1fnoise from surface generation and annihilation: Application to metal films

A model in which a conserved quantity enters and leaves a diffusing medium at a bounding surface is discussed. Fluctuations in the rate at which the quantity enters or leaves lead to density fluctuations in the medium. These density fluctuations diffuse and eventually leave the medium with a time dependence correlated with the initial fluctuation. The Fourier transform of this time dependence gives $\frac{1}{f}$ noise. This model is applied to voltage noise in thin metal films. The diffusing quantities which are used and which affect the conductivity are phonon energy and vacancies. Order-of-magnitude agreement with experiment is obtained.