Acoustic phonon impact on the inter-Coulombic decay process in charged quantum dot pairs

ABSTRACT

Recently, highly accurate multi-configuration time-dependent Hartree electron dynamics calculations demonstrated the efficient long-range energy transfer inter-Coulombic decay (ICD) process to happen in charged semiconductor quantum dot (QD) pairs. ICD is initiated by intraband photoexcitation of one of the QDs and leads to electron emission from the other within a duration of about 150 ps. On the same time scale electronically excited states are reported to relax due to the coupling of electrons to acoustic phonons. Likewise, phonons promote ionisation. Here, the QDs' acoustic breathing mode is implemented in a frozen-phonon approach. A detailed comparison of the phonon effects on electron relaxation and emission as well as on the full ICD process is presented, which supports the previous empirical finding of ICD being the dominant decay channel in paired QDs. In addition the relative importance of phonon–phonon, phonon–electron and electron–electron interaction is analysed.

GRAPHICAL ABSTRACT

KEYWORDS:

• Quantum dots
• electron dynamics
• inter-Coulombic decay
• resonance states
• phonons

Acknowledgements

In 2011 Nimrod Moiseyev and I published both our first paper on QD–ICD with different models and methodologies. I am grateful for our discussions in that time in which I learned more from Nimrod's different viewing angle. Another view has significantly been inspired by the curiosity of the scientific community on the role of phonons in QD–ICD. Several people deserve thank for helping me answering this question. Particularly, I would like to thank Ioan Baldea for introducing me to theories of phonons in nanomaterials, Andreas Komnik, who sketched the applied phonon description, Fabian Langkabel for typesetting the manuscript as well as the internship students Lena Steuer, Maik Rudolff and Joana-Lysiane Schäfer, who performed first test calculations.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

A. Bande  http://orcid.org/0000-0003-3827-9169

Additional information

Funding

The work was supported by the German Science Foundation [grant number BA 3770/2-1]; the Volkswagen foundation under the Freigeist fellowship 89525.