Photon-Assisted Transport Through Ultrasmall Quantum Dots: Influence of Intradot Transitions

TL;DR

This paper investigates photon-assisted electron transport in ultrasmall quantum dots with multiple energy levels under AC fields, introducing a generalized approximation method and proposing a novel electron pump design.

Contribution

It develops a generalized rotating-wave approximation for multi-level quantum dots and proposes a new electron pump device based on coupled quantum dots.

Findings

Calculated dc-current aligns with recent experimental results.

Demonstrated the effect of AC fields on interlevel transitions.

Proposed a novel electron pump using coupled quantum dots.

Abstract

We study transport through one or two ultrasmall quantum dots with discrete energy levels to which a time-dependent field is applied (e.g., microwaves). The AC field causes photon-assisted tunneling and also transitions between discrete energy levels of the dot. We treat the problem by introducing a generalization of the rotating-wave approximation to arbitrarily many levels. We calculate the dc-current through one dot and find satisfactory agreement with recent experiments by Oosterkamp et al. . In addition, we propose a novel electron pump consisting of two serially coupled single-level quantum dots with a time-dependent interdot barrier.