Dresden 2026 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 41: Development of Calculation Methods II

MM 41.9: Vortrag

Freitag, 13. März 2026, 12:30–12:45, SCH/A251

Defect-induced vibrational modes in graphene — •Iskander Mukatayev, Guillaume Radtke, and Michele Lazzeri — Sorbonne Université, CNRS UMR 7590, MNHN, IMPMC, 4 place Jussieu, 75252 Paris, France

We present a general framework for investigation of the vibrational properties of point defects in graphene, motivated by recent advances in vibrational EELS that enable phonon spectroscopy with atomic resolution. Our approach combines DFT and density-functional perturbation theory with a force-matching procedure [1-2], in which interatomic force constants (IFCs) are computed independently for pristine graphene and defect-containing supercells and then merged to dynamical matrices of very large systems(up to 20000 atoms). This strategy enables the modeling of isolated defects without defect-defect interactions while retaining full ab initio accuracy.

We investigate a wide range of point defects including substitutional dopants (B, N, Si, P), single, double vacancies and Stone-Wales reconstruction. Depending on the details of defect-induced bond reconstruction, different behaviours are observed ranging from quasi-localized (or resonant) states falling in the continuum of the bulk to high-frequency fully localised modes. From these examples we draw conclusions of the conditions of occurrence of both types vibrations.

References

1. M. Lazzeri, P. Thibaudeau, Phys. Rev. B 74, 140301 (2006)

2. G. Radtke, S. Klotz, M. Lazzeri, P. Loubeyre, M. Krisch, A. Bossak, Phys. Rev. Lett. 132, 056102 (2024)

Keywords: graphene; phonons; DFT; force constants; defects