Shot noise in diffusive conductors: A quantitative analysis of electron-phonon interaction effects

Using the 'drift-diffusion-Langevin' equation, we have quantitatively analyzed the effects of electron energy relaxation via their interaction with phonons, generally in presence of electron-electron interaction, on shot noise in diffusive conductors. We have found that the noise power SI(ω) (both at low and high observation frequencies ω) drops to half of its 'mesoscopic' value only at β approx-gt 100, where β is the ratio of the sample length L to the energy relaxation length lph (the latter may be much larger then the dephasing length). It means in particular that at low temperatures the shot noise may be substantial even when L∼10-2 - 10-1cm, and the conductor is 'macroscopic' in any other respect. copyright 1998 The American Physical Society