Acoustic Phonon Anomaly in MgB2

Abstract

Recent first principles calculations of the phonon dispersion curves in MgB_2 have suggested the presence of anomalies in some of the curves, particularly in the longitudinal acoustical (LA) branch in the Gamma to A direction. Similar behavior has been observed in numerous other superconductors with T_c's higher than those of standard electron-phonon BCS superconductors. Phenomenological calculations of the Gamma->A LA dispersion based on both an acoustical plasmon and a ``resonant polarization'' mechanism are given here to emphasize the importance of these similarities.

4+ pages, 3 figures, RevTeX 4, revised version, accepted to PRB

References in corpus (8)

• Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors
• Superconductivity of metallic boron in MgB_2
• Electron-phonon interaction in the normal and superconducting states of MgB2
• Phonon dispersion and electron-phonon coupling in MgB_2 and AlB_2
• Giant anharmonicity and non-linear electron-phonon coupling in MgB${}_2$; A combined first-principles calculations and neutron scattering study
• Detailed electronic structure studies on superconducting MgB${}_2$ and related compounds
• Mixed lattice and electronic states in high-temperature superconductors
• Ab Initio Investigation of Collective Charge Excitations in MgB_2