Structural, elastic and electronic properties of CuYO2 from first-principles study

Abstract

The structural, elastic and electronic properties of CuYO2 have been investigated by the plane wave pseudopotential density functional theory (DFT) within the local density approximation (LDA) and the LDA+U methods. The strong on-site Coulomb repulsion of the localized Cu 3d electrons and Y 4d electrons are amended by LDA+U formalism, showing that the properties of CuYO2 are quite sensitive to the change of the value of U; the optimized choice of U is 6eV plusing to the 3d state of the Cu atoms. Through the LDA+U correction, the calculated lattice constants, insulating gap and bulk modulus agree well with the available experimental and other theoretical data. Moreover, the anisotropies, the compressional and shear wave velocities, Young’s modulus, Poisson’s ratio, as well as the Debye temperature have been calculated for U=6eV, which are compared with those for U=0eV. It has been found that the predicted elastic constants, bulk modulus, shear modulus, acoustic velocities, anisotropy factor and Debye temperature of CuYO2 are slightly fluctuant with the increase of the U value. The calculated results also show that, the valence band of CuYO2 mainly composed of the 3d state of the Cu and the 2p state of the O, while the conduction band mainly composed of the 4d state of the Y.