Kohn anomalies and electron-phonon interactions in graphite.
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, while they are negligible for all the other modes at Gamma and K.
Piscanec
S
S
Cambridge University, Engineering Department, Trumpington Street, Cambridge CB2 1PZ, United Kingdom.
Lazzeri
M
M
Mauri
Francesco
F
Ferrari
A C
AC
Robertson
J
J