Electrically Tunable Fine Structure of Negatively Charged Excitons in Gated Bilayer Graphene Quantum Dots

Fuente: arXiv
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Main Authors: Sadecka, Katarzyna, Saleem, Yasser, Miravet, Daniel, Albert, Matthew, Korkusinski, Marek, Bester, Gabriel, Hawrylak, Pawel
Format: Preprint
Published: 2023
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author Sadecka, Katarzyna
Saleem, Yasser
Miravet, Daniel
Albert, Matthew
Korkusinski, Marek
Bester, Gabriel
Hawrylak, Pawel
author_facet Sadecka, Katarzyna
Saleem, Yasser
Miravet, Daniel
Albert, Matthew
Korkusinski, Marek
Bester, Gabriel
Hawrylak, Pawel
contents We predict here the fine structure of an electrically tunable negatively charged exciton (trion) composed of two electrons and a hole confined in a gated bilayer graphene quantum dot (QD). We start with an atomistic approach, allowing us to compute confined electron and confined hole QD states for a structure containing over one million atoms. Using atomistic wavefunctions we compute Coulomb matrix elements and self-energies. In the next step, by solving the Bethe-Salpeter-like equation for trions, we describe a negatively charged exciton, built as a strongly interacting interlayer complex of two electrons in the conduction band and one hole in the valence band. Unlike in conventional semiconducting QDs, we show that the trion contains a fine structure composed of ten states arising from the valley and spin degrees of freedom. Finally, we obtain absorption into and emission from the trion states. We predict the existence of bright low-energy states and propose to extract the fine structure of the trion using the temperature dependence of emission spectra.
format Preprint
id arxiv_https___arxiv_org_abs_2312_06264
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Electrically Tunable Fine Structure of Negatively Charged Excitons in Gated Bilayer Graphene Quantum Dots
Sadecka, Katarzyna
Saleem, Yasser
Miravet, Daniel
Albert, Matthew
Korkusinski, Marek
Bester, Gabriel
Hawrylak, Pawel
Mesoscale and Nanoscale Physics
We predict here the fine structure of an electrically tunable negatively charged exciton (trion) composed of two electrons and a hole confined in a gated bilayer graphene quantum dot (QD). We start with an atomistic approach, allowing us to compute confined electron and confined hole QD states for a structure containing over one million atoms. Using atomistic wavefunctions we compute Coulomb matrix elements and self-energies. In the next step, by solving the Bethe-Salpeter-like equation for trions, we describe a negatively charged exciton, built as a strongly interacting interlayer complex of two electrons in the conduction band and one hole in the valence band. Unlike in conventional semiconducting QDs, we show that the trion contains a fine structure composed of ten states arising from the valley and spin degrees of freedom. Finally, we obtain absorption into and emission from the trion states. We predict the existence of bright low-energy states and propose to extract the fine structure of the trion using the temperature dependence of emission spectra.
title Electrically Tunable Fine Structure of Negatively Charged Excitons in Gated Bilayer Graphene Quantum Dots
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2312.06264