Existence of erbium hexaboride nanowires

The existence and stability of erbium hexaboride (ErB₆) has been a controversial topic in literature due to cited failures in reproducing previous synthetic results. Here, we report our proof of the existence of ErB₆ by demonstrating the synthesis of a mixture of ErB₆ nanowires and erbium tetraboride (ErB₄) nanoplatelets via palladium nanoparticle-assisted chemical vapor deposition. High-resolution transmission electron microscopy and selected-area electron diffraction showed that both the ErB₆ nanowires and ErB₄ nanoplatelets were single crystalline with expected cubic and tetragonal crystal structures, respectively. The observed lattice constants compared well with the theoretical structures calculated using density functional theory.