Contribution of the Si s Electronic State to the Density of State of CoSi2 at Fermi Energy by Soft X-Ray Emission Spectroscopy

Abstract
A clear modification is observed between an electron-excited Si L2.3 valence band (VB) soft X-ray emission spectrum (SXES) for CoSi2 and the one for Si. From this fact, it is concluded that a fair amount of the Si s electronic state is included in the upper half, especially at the Fermi edge, of the VB density of state (VB-DOS) of CoSi2. This fact is a clear contrast to many proposals given so far, where it is claimed that the upper part of the VB-DOS of CoSi2 is constructed only by the electronic states due to Co(3d)-Si(3p) hybridization.