Observation of the hole state symmetry of MgB_2 by inelastic scattering of fast electrons accompanied by boron K-shell excitation

摘要

The symmetry of the p-hole state of a superconductor of MgB_2 was studied by the observation of inelastic scattering anisotropy of fast electrons accompanied by boron K-shell excitation. A series of the energy-selected diffraction patterns taken at successive energy losses were decomposed into two components; the σ and π components, respectively. The magnitudes of the σ and π components as a function of energy loss, or partial electron energy-loss spectroscopy spectra, show a good correspondence to the partial density of states obtained by a theoretical calculation. A significant occupation of the σ state at just above the Fermi level, which is considered to play an important role for the formation of the superconductive state, was confirmed.