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arXiv · 2109.08733

Quantum Confinement of Electron-Phonon Coupling in Graphene Quantum Dots

Marios Zacharias·Pantelis C. Kelires
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Abstract

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.

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Marios Zacharias, Pantelis C. Kelires. 2021-09-17. Quantum Confinement of Electron-Phonon Coupling in Graphene Quantum Dots. https://doi.org/10.1021/acs.jpclett.1c02899

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