Nonadiabatic Kohn Anomaly in Heavily Boron-Doped Diamond

We report evidence of a nonadiabatic Kohn anomaly in boron-doped diamond, using a joint theoretical and experimental analysis of the phonon dispersion relations. We demonstrate that standard calculations of phonons using density-functional perturbation theory are unable to reproduce the dispersion r...

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Published inPhysical review letters Vol. 119; no. 1; p. 017001
Main Authors Caruso, Fabio, Hoesch, Moritz, Achatz, Philipp, Serrano, Jorge, Krisch, Michael, Bustarret, Etienne, Giustino, Feliciano
Format Journal Article
LanguageEnglish
Published United States 07.07.2017
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Summary:We report evidence of a nonadiabatic Kohn anomaly in boron-doped diamond, using a joint theoretical and experimental analysis of the phonon dispersion relations. We demonstrate that standard calculations of phonons using density-functional perturbation theory are unable to reproduce the dispersion relations of the high-energy phonons measured by high-resolution inelastic x-ray scattering. On the contrary, by taking into account nonadiabatic effects within a many-body field-theoretic framework, we obtain excellent agreement with our experimental data. This result indicates a breakdown of the Born-Oppenheimer approximation in the phonon dispersion relations of boron-doped diamond.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.119.017001