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arXiv · 2506.18704

Importance of Non-Adiabatic Effects on Kohn Anomalies in 1D metals

Enrico Marazzi·Samuel Poncé·Jean-Christophe Charlier·Gian-Marco Rignanese
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Abstract

Kohn anomalies are kinks or dips in phonon dispersions which are pronounced in low-dimensional materials. We investigate the effects of non-adiabatic phonon self-energy on Kohn anomalies in one-dimensional metals by developing a model that analyzes how the adiabatic phonon frequency, electron effective mass, and electron-phonon coupling strength influence phonon mode renormalization. We introduce an electron-phonon coupling strength threshold for low-temperature system instability, providing experimentalists with a tool to predict them. Finally, we validate the predictions of our model against first-principles calculations on a 4 {\AA}-diameter carbon nanotube.

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Enrico Marazzi, Samuel Poncé, Jean-Christophe Charlier, Gian-Marco Rignanese. 2025-06-23. Importance of Non-Adiabatic Effects on Kohn Anomalies in 1D metals. https://doi.org/10.1103/x69r-8fw1

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