Year: 2004
Type: article
Abstract: We demonstrate that graphite phonon dispersions have two Kohn anomalies at the $\ensuremath{\Gamma}\mathrm{\text{\ensuremath{-}}}{E}_{2g}$ and $\mathbf{K}\mathrm{\text{\ensuremath{-}}}{A}_{1}^{\ensuremath{'}}$ 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 $\ensuremath{\Gamma}\mathrm{\text{\ensuremath{-}}}{E}_{2g}$ and $\mathbf{K}\mathrm{\text{\ensuremath{-}}}{A}_{1}^{\ensuremath{'}}$ EPCs are particularly large, while they are negligible for all the other modes at $\ensuremath{\Gamma}$ and $\mathbf{K}$.
Source: Physical Review Letters
Institution: University of Cambridge
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2049862697