First-principles study of low compressibility osmium borides

摘要

Using first-principles total energy calculations we investigate the structural, elastic, and electronic properties of OsB_2 and OsB, respectively. The calculated equilibrium structural parameters of OsB_2 are in agreement with the available experimental results. The calculations indicate that OsB in tungsten carbide is more energetically stable under the ambient condition than the metastable cesium chloride phase of OsB. Results of bulk modulus show that they are potential low compressible materials. The hardness of OsB_2 is estimated by employing a semiempirical theory. The results indicate that OsB_2 is an ultraincompressible material, but not a superhard material. The method designing superhard materials is different from one creating ultraincompressible materials.