Characterization of the electronic properties of YB₁₂, ZrB₁₂, and LuB₁₂using¹¹B NMR and first-principles calculations

Abstract

Three metallic dodecaborides, YB12, ZrB12 and LuB12, have been investigated by electric-field gradient (EFG) measurements at the boron sites using the 11B nuclear magnetic resonance (NMR) technique and by performing first-principles calculations. The NMR powder spectra reveal patterns typical for a completely asymmetric EFG tensor, i.e., an η parameter close to unity. The absolute values of Vzz (the largest component of the EFG) are determined from the spectra and they range between 11 × 1020 V m−2 and 11.6 × 1020 V m−2 with an uncertainty of 0.8 × 1020 V m−2, being in very good agreement with the first-principles results. In addition the electronic structure and chemical bonding are analysed from partial densities of states and electron densities.