Ab Initio Investigation of Collective Charge Excitations in MgB_2

Abstract

A sharp collective charge excitation is predicted in MgB${}_2$ at $\sim 2.5eV$ for $q$ perpendicular to the boron layers, based on an all-electron analysis of the dynamical density response within time-dependent density functional theory. This novel excitation, consisting of coherent charge fluctuation between Mg and B sheets, induces an abrupt plasma edge in the experimentally-observable reflectivity. The existence of this mode reflects the unique electronic structure of MgB${}_2$, that is also responsible for strong electron-phonon coupling. By contrast, the acoustic plasmon, recently suggested to explain the high $T_c$, is not realized when realistic transition strengths are incorporated.

4 pages, 4 figures. accepted for publication by Phys. Rev. Lett

References in corpus (7)

• Superconductivity of metallic boron in MgB_2
• Beyond Eliashberg superconductivity in MgB2: anharmonicity, two-phonon scattering, and multiple gaps
• Boron Isotope Effect in Superconducting MgB${}_2$
• Superconductivity of MgB2: Covalent Bonds Driven Metallic
• Electron-phonon interaction in the normal and superconducting states of MgB2
• Soft x-ray spectroscopy measurements of the p-like density of states of B in MgB2 and evidence for surface boron oxides on exposed surfaces
• Two-Band-Type Superconducting Instability in MgB2

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