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 $S_I\left(\omega \right)$ (both at low and high observation frequencies $\omega )$ drops to half of its “mesoscopic” value only at $\beta \gtrsim 100,$ where $\beta$ is the ratio of the sample length L to the energy relaxation length $l_{\mathrm{ph}}$ (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 $L\sim {10}^{-2}–{10}^{-1}\mathrm{c}\mathrm{m},$ and the conductor is “macroscopic” in any other respect.

• Received 27 March 1998

DOI:https://doi.org/10.1103/PhysRevB.58.15371