Dynamic scattering channels of a double barrier structure

TL;DR

This paper analytically derives the Floquet scattering matrix for a driven double-barrier system, revealing how dynamical effects influence electron transport and current generation under fast driving conditions.

Contribution

It introduces a method to represent the Floquet scattering amplitude as a sum over dynamical channels, accounting for fast-drive effects in quantum transport.

Findings

Dynamical scattering channels are characterized by different times spent inside the structure.

The dc current comprises photon-assisted intra-channel and inter-channel interference contributions.

At high temperature or frequency, only intra-channel interference significantly contributes to the current.

Abstract

We calculate analytically the Floquet scattering matrix for a periodically driven double-barrier structure. Our approach takes into account dynamical effects which become necessarily important when electrons propagate through a system subject to a fast drive. It is convenient to represent the Floquet scattering amplitude as a sum of amplitudes corresponding to different times spent by an electron inside the structure. These amplitudes define dynamical scattering channels. Then we represent the dc current generated by the structure as a sum of two generic contributions. The first one is due to photon-assisted interference processes within the same channel and the second one is due to inter-channel interference processes. At zero temperature both contributions are present while at high temperatures and/or high driving frequencies only the former survives.