Kohn Anomalies and Electron-Phonon Interaction in Graphite

S. Piscanec , M. Lazzeri (1) , Francesco Mauri (1) , A. C. Ferrari , J. Robertson

1 IMPMC - Institut de minéralogie et de physique des milieux condensés

We demonstrate that graphite phonon dispersions have two Kohn anomalies at the Gamma-E_2g and K-A\'1 modes. The anomalies are revealed by two sharp kinks. By an exact analytic derivation, we show that the slope of these kinks is proportional to the square of the electron-phonon coupling (EPC). Thus, we can directly measure the EPC from the experimental dispersions. The Gamma-E_2g and K-A\'1 EPCs are particularly large, whilst they are negligible for all the other modes at Gamma and K.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S. Piscanec, M. Lazzeri, Francesco Mauri, A. C. Ferrari, J. Robertson. Kohn Anomalies and Electron-Phonon Interaction in Graphite. Physical Review Letters, 2004, 93, pp.185503. ⟨hal-00019391⟩