Atomic-Orbital Analysis of ZrB₂Valence-Band by Two-Dimensional Photoelectron Spectroscopy

To investigate the electronic state of Zirconium diboride (ZrB₂) (0001) clean surface, we measured two-dimensional photoelectron intensity angular distribution (PIAD) patterns with a display-type spherical mirror analyzer (DIANA). As a result, we obtained two-dimensional band dispersion cross section patterns of ZrB₂. In these patterns, we observed the transition-matrix-element effect of linearly-polarized light excitation. Comparing the experimental data to the calculation results, we concluded that the band at the K point at a binding energy of 3.4 eV consists of B 2<i>p</i>_z, Zr 4<i>d</i>_yz, and Zr 4<i>d</i>_zx orbitals. This suggests that this band is the bonding state between the B layer and the Zr layer. We confirmed that this hybrid orbital, where the <i>d</i> electrons of Zr are donated to the <i>p</i>_z orbital of B, makes the Dirac-cone-like band of ZrB₂. [DOI: 10.1380/ejssnt.2015.324]