Quantum Confinement of Electron–Phonon Coupling in Graphene Quantum Dots

On the basis of first-principles calculations and the special displacement method, we demonstrate the quantum confinement scaling law of the phonon-induced gap renormalization of graphene quantum dots (GQDs). We employ zigzag-edged GQDs with hydrogen passivation and embedded in hexagonal boron nitri...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2021-10, Vol.12 (40), p.9940-9946
Main Authors: Zacharias, Marios, Kelires, Pantelis C
Format: Article
Language:English
Subjects:
Physical Insights into Materials and Molecular Properties
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Summary:On the basis of first-principles calculations and the special displacement method, we demonstrate the quantum confinement scaling law of the phonon-induced gap renormalization of graphene quantum dots (GQDs). We employ zigzag-edged GQDs with hydrogen passivation and embedded in hexagonal boron nitride. Our calculations for GQDs in the sub-10 nm region reveal strong quantum confinement of the zero-point renormalization ranging from 20 to 250 meV. To obtain these values we introduce a correction to the Allen–Heine theory of temperature-dependent energy levels that arises from the phonon-induced splitting of 2-fold degenerate edge states. This correction amounts to more than 50% of the gap renormalization. We also present momentum-resolved spectral functions of GQDs, which are not reported in previous contributions. Our results lay the foundation to systematically engineer temperature-dependent electronic structures of GQDs for applications in solar cells, electronic transport, and quantum computing devices.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.1c02899