Electron-phonon interactions in magnesium measured by inelastic neutron scattering

The fine structure of low-energy phonon dispersion branches in Mg has been investigated by inelastic neutron scattering. The irregularities observed in the photon group velocity are a kind of Kohn anomaly. They are compared with those determined in Cd. Theoretical calculations of the fine structure in Mg were made in a new way by taking band gaps into account. The theory explains the difference between Mg and Cd quite well, but fails to describe the experimental data quantitatively. In particular, the varying strength of different anomalies are not reproduced.