Valence Band Photoemission Studies of LiGa Zintle Intermetallic Compound

Abstract

The valence band photoemission spectra of LiGa Zintl intermetallic compound were measured at various photon energies by using a synchrotron radiation source, and were compard with the existing RAPW band structure calculations. The very low intensity of photoemission from the top of the valence band indicates that the s-to-p charge promotion believed to explain the bonding in this Zintl compound is less significant than that predicted by theory. The measured binding energy of 18.8 eV of the Ga-3d doublet states places these states about 7.7 eV below the bottom of the valence band, in contrast with the calculated value of 4.5 eV. A clear structure observed at 13 eV binding energy has no counterpart in the theoretical DOS distribution. Its ambiguous origin is discussed in relation to possible interband excitations, or its incorporation into a wider valence band than that resulting from the RAPW theory.