SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 30: 2D Materials I: Electronic Structure
O 30.8: Vortrag
Dienstag, 28. März 2023, 12:15–12:30, GER 37
Excited state geometry relaxation of point defects in hexagonal boron nitride — •Alexander Kirchhoff, Thorsten Deilmann, and Michael Rohlfing — Westfälische Wilhelms-Universität Münster, Institut für Festkörpertheorie, Wilhelm-Klemm-Straße 10, 48149 Münster
The optical gap of pristine hexagonal boron nitride is above 5 eV and therefore in the deep UV range.
Emitters in the optical regime can act as single photon sources and gained attraction due to their possible room temperature stability.
However, their atomic composition is still elusive.
Experiments combining spectroscopic methods to probe ground as well as excited state of defects in hBN have revealed the relevance of the dependence of optoelectronic properties on the nuclear geometry.
In our work, this dependence is studied within the framework of density functional theory and the GW/BSE approximation.
We focus on carbon based defects in hBN and present a detailed analysis of their excitonic spectrum [1].
CBON for example has a defect bound exciton at 1.5 eV. We obtain a Stokes shift of about 1 eV by calculating the energy surfaces of ground and excited state.
[1] Kirchhoff, Deilmann, Krüger and Rohlfing, Phys. Rev. B 106, 045118 (2022)