Nonlinear Transport Properties of Quantum Dots

TL;DR

This paper investigates how excited states influence the nonlinear transport behavior of quantum dots, revealing effects like Coulomb blockade, conductance asymmetry, and negative differential conductance through theoretical models.

Contribution

It introduces a comparative analysis of classical charging and quantum models to explain excited state effects on quantum dot transport properties.

Findings

Coulomb blockade and fine structure observed in current-voltage curves

Asymmetric conductance peaks due to unequal lead coupling

Negative differential conductance predicted from excited states with different spins

Abstract

The influence of excited levels on nonlinear transport properties of a quantum dot weakly coupled to leads is studied using a master--equation approach. A charging model for the dot is compared with a quantum mechanical model for interacting electrons. The current--voltage curve shows Coulomb blockade and additional finestructure that is related to the excited states of the correlated electrons. Unequal coupling to the leads causes asymmetric conductance peaks. Negative differential conductances are predicted due to the existence of excited states with different spins.