Noise properties and ac conductance of mesoscopic diffusive conductors with screening

A theory of nonequilibrium (“shot”) noise and high-frequency conductance in diffusive mesoscopic conductors with screening is presented. Detailed results are obtained for two simple geometries, for both large and short electron-electron scattering length (Formula presented) at frequencies of the order of the inverse Thouless time (Formula presented) The conductance and the noise are found to exhibit significant frequency dependence. For (Formula presented) the high-frequency (Formula presented) shot-noise spectral density (Formula presented) approaches a finite value between (Formula presented) and (Formula presented) depending on the screening properties of the system, with temperature corrections to (Formula presented) being linear in (Formula presented) However, when (Formula presented) (Formula presented) grows as (Formula presented) (at (Formula presented) is not upper-bound by (Formula presented) and has a temperature-dependent component quadratic in (Formula presented) As a result, measurements of (Formula presented) can be utilized as a probe of the strength of electron-electron scattering.