Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 72: 2D Materials 3: hBN and Electronic Structure

O 72.6: Talk

Thursday, September 8, 2022, 16:15–16:30, S052

Diversity of defect-related excitons in hBN from ab initio calculations — •Alexander Kirchhoff, Thorsten Deilmann, Peter Krüger, and Michael Rohlfing — Westfälische Wilhelms-Universität Münster, Institut für Festkörpertheorie, Wilhelm-Klemm-Straße 10, 48149 Münster

While pristine hexagonal boron nitride (hBN) is an insulator with an optical gap of ∼5 eV, point defects in this material are discussed as single-photon emitters in the visible optical spectrum. In this study, we examine different defects consisting of carbon or oxygen substitutions and vacancies in an hBN monolayer from an ab initio approach, via the GW/BSE approximation. Our results show deep defect states and defect-related excitations with energies in the visible regime. We present a detailed analysis of their structure and energetic composition and furthermore discuss the dependence of the excitonic spectrum on the geometry. Finally, we present a defect of two carbon substitutions adjacent to a divacancy, which shows an antiferromagnetic ground state.