Elastic Properties of Orthorhombic YBa2Cu3O7 under Pressure

The pressure dependence of the lattice and elastic constants of the orthorhombic YBa2Cu3O7 are firstly investigated using the first principles calculations based on the density functional theory. The calculated lattice parameters at 0 GPa are in agreement with the available experimental data. By the elastic stability criteria under isotropic pressure, it is predicted that YBa2Cu3O7 with and orthorhombic structure is mechanically stable under pressure up to 100 GPa. On the basis of the elastic constants, Pugh's modulus ratio, Poisson's ratio, elastic anisotropy, Debye temperature, and the minimum thermal conductivity of YBa2Cu3O7 under pressure up to 100 GPa are further investigated. It is found that its ductility, Debye temperature, and minimum thermal conductivity increase with pressure.