Electronic structure of nanopolycrystalline pulsed laser deposited LaB6 films and single crystals: The boron perspective

摘要

We report an investigation of the electronic structure of LaB6 nanopolycrystalline pulsed laser deposited (PLD) film and single crystal with x-ray absorption near edge structures (XANES) spectroscopy at the B K-edge. The experimental results are compared with theoretical calculations using density functional theory, and real space multiple scattering. It is found that (i) the LaB6 PLD film is of high quality and metallic albeit it is a polycrystalline phase of nanocrystallites and (ii) the B K-edge XANES for the single crystal specimens exhibit well defined spectral features corresponding to the theoretical partial densities of states of B p character and the threshold energy is relatively low and free electronlike, revealing its metallic character. The implications of these observations to the enhancement in electron emission from the PLD films are discussed.