Inelastic Scattering from Local Vibrational Modes

TL;DR

This paper investigates how local vibrational modes cause inelastic scattering of conduction electrons, revealing oscillatory behavior and saturation effects that impact dephasing in mesoscopic systems.

Contribution

It introduces a detailed analysis of nonuniversal inelastic scattering contributions from local vibrational modes, emphasizing multiphonon effects and strong coupling behavior.

Findings

Inelastic scattering rate exhibits oscillations due to multiphonon excitations.

At high frequencies, the scattering rate saturates to a finite value.

Strong coupling leads to phonon softening and maximal inelastic cross section.

Abstract

We study a nonuniversal contribution to the dephasing rate of conduction electrons due to local vibrational modes. The inelastic scattering rate is strongly influenced by multiphonon excitations, exhibiting oscillatory behaviour. For higher frequencies, it saturates to a finite, coupling dependent value. In the strong coupling limit, the phonon is almost completely softened, and the inelastic cross section reaches its maximal value. This represents a magnetic field insensitive contribution to the dephasing time in mesoscopic systems, in addition to magnetic impurities.