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arXiv · 0801.1291

Chirality-induced Dynamic Kohn Anomalies in Graphene

Wang-Kong Tse·Ben Yu-Kuang Hu·S. Das Sarma
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Abstract

We develop a theory for the renormalization of the phonon energy dispersion in graphene due to the combined effects of both Coulomb and electron-phonon (e-ph) interactions. We obtain the renormalized phonon energy spectrum by an exact analytic derivation of the phonon self-energy, finding three distinct Kohn anomalies (KAs) at the phonon wavevector $q = ω/v, 2k_F\pmω/v$ for LO phonons and one at $q = ω/v$ for TO phonons. The presence of these new KAs in graphene, in contrast to the usual KA $q = 2k_F$ in ordinary metals, originates from the dynamical screening of e-ph interaction (with a concomitant breakdown of the Born-Oppenheimer approximation) and the peculiar chirality of the graphene e-ph coupling.

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Wang-Kong Tse, Ben Yu-Kuang Hu, S. Das Sarma. 2008-07-18. Chirality-induced Dynamic Kohn Anomalies in Graphene. https://doi.org/10.1103/physrevlett.101.066401

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