VERY LONG DECAY TIME FOR ELECTRON VELOCITY DISTRIBUTION IN SEMICONDUCTORS, AND CONSEQUENT 1/f NOISE

Abstract

The Boltzmann equation with electron-electron (e − e) interactions has been reduced to a Fokker-Planck equation (e − e FP ) in a previuos paper. In steady-state conditions, its solution q0(v) (where v is the electron speed) depends on the square of the acceleration a = eE/m. If we introduce the nonrenormalized zero-point field (ZPF) of QED, i.e., the one considered in stochastic electrodynamics, so that [Formula: see text], then q0(v) becomes similar to the Fermi-Dirac equation, and the two collision frequencies ν1(v) and ν2(v) appearing in the e − e FP become both proportional to 1/v in a small δv interval. The condition ν1(v) ∝ ν2(v) ∝ 1/v is at the threshold of the runaways. In the same δv range, the time-dependent solution q0(v,τ) of the e − e FP decays no longer exponentially but according to a power law ∝ τ− ɛ where 0.004 < ɛ < 0.006, until τ → ∞. That extremely long memory of a fluctuation implies the same dependence τ − ɛ for the conductance correlation function, hence a corresponding power-spectral noise S(f) ∝ fɛ−1 where f is the frequency. That behaviour is maintained even for a small sample because the back diffusion velocity of the electrons in the effective range δv, where they are in runaway conditions, is much larger than the drift velocity.