Structure Analysis of ZrB2(0001) Surface Prepared byex situHF Treatment

The surface structure of ZrB2(0001) was investigated using coaxial impact-collision ion scattering spectroscopy (CAICISS). The ZrB2(0001) 1×1 surface was prepared by HF solution treatment and annealing in vacuum. It was directly evidenced that the ZrB2(0001) surface is terminated with a Zr layer. Moreover, we found that the interlayer spacing between the first Zr layer and the second B layer is expanded by 20% with regard to c-axis lattice constant. Since small amount of O atoms were detected after the cleaning, the incorporation of the residual O atoms into the subsurface region of the ZrB2(0001) surface is likely to be the origin of the large expansion.