Intermittent Phonon Scattering as a Possible Origin of 1/f Fluctuations in Metallic Resistors

We regard a metallic resistor for temperatures T ≫ Θ D (= Debye temperature); under this condition, electron–phonon scattering is the dominant scattering mechanism. We investigate the noise properties under the supposition that phonon scattering is an intermittent process. Intermissions may be caused by an interaction between different phonon modes giving rise to a short break down of a mode. Due to such an intermittent behavior, we obtain — besides thermal noise — a 1/f noise component. Under equilibrium conditions, the 1/f noise term disappears. Under an applied electric field, the electrons are accelerated between collisions resulting in an additional 1/f noise component which can be compared with Hooge's relation. The predicted Hooge coefficient is α ≈ 3 ⋅ 10-3(τ off /τs)2 with τs being the mean electron phonon scattering time and τ off being the mean off-time ( = intermission). We also find 1/f fluctuations in the square of thermal noise suggesting that an applied current only probes 1/f fluctuations which are already present under equilibrium conditions.