Electron–phonon renormalization and phonon anharmonicity in metals

Electron–phonon renormalization and phonon anharmonicity in metals are investigated by employing density functional theory based first-principles electronic structure methods. Using doped silicon, diamond, and MgB2 as examples, it is shown that phonon anharmonicity may be significantly renormalized by electron–phonon interactions, especially for phonon modes that couple strongly with electrons. The unusually large third-order anharmonic potential of the E 2 g phonon in MgB2 is largely due to the electron–phonon renormalization effect.