Elastic properties of transition metal dioxides: XO₂(X=Ru, Rh, Os, Ir)

The elastic properties of rutile transition metal dioxides XO$_{2}$ (X=Ru, Rh, Os, and Ir) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO$_2$ and IrO$_2$ show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.