Effects of screened Coulomb impurities on autoionizing two-electron resonances in spherical quantum dots

TL;DR

This paper investigates how screened Coulomb impurities near spherical quantum dots influence autoionizing two-electron resonances, revealing that impurities can disrupt control over bound-to-resonant transitions and affect electron transport.

Contribution

It demonstrates that Coulomb impurities can alter autoionizing resonances and transition behaviors in quantum dots, adding complexity to their electronic control mechanisms.

Findings

Impurities cause avoided crossings in resonance states.

Impurities can disrupt control of transition lifetimes.

Impurities impact electron transport in quantum dot arrays.

Abstract

In a recent paper (Phys. Rev. B {\bf 78}, 075316 (2008)), Sajeev and Moiseyev demonstrated that the bound-to-resonant transitions and lifetimes of autoionizing states in spherical quantum dots can be controlled by varying the confinment strength. In the present paper, we report that such control can in some cases be compromised by the presence of Coulomb impurities. It is demonstrated that a screened Coulomb impurity placed in the vicinity of the dot center can lead to bound-to-resonant transitions and to avoided crossings-like behavior when the screening of the impurity charge is varied. It is argued that these properties also can have impact on electron transport through quantum dot arrays.