First principles LDA+U and GGA+U study of HfO2: Dependence on the effective U parameter

Authors : Yasemin ÇİFTÇİ, A. ERGUN, K. COLAKOGLU, E. DELIGOZ

Pages : 627-636

View : 14 | Download : 6

Publication Date : 2014-03-28

Article Type : Conference Paper

Abstract :We have performed first-principles calculations of the structural, electronic, mechanical, and vibrational  properties of HfO2 based on the density functional theory with Local Density Approximation insert ignore into journalissuearticles values(LDA);,  Generalized Gradient Approximationinsert ignore into journalissuearticles values(GGA);, the LDA + U and GGA+U approaches based on the density  functional theory insert ignore into journalissuearticles values(DFT);. In orderd to describe precisely the strong on-site Coulomb repulsion among the  localized Hf 5d electrons, we adopt the LDA+U and GGA+U formalism for the exchange correlation term. For  the total-energy calculation we have used the projected augmented plane-wave insert ignore into journalissuearticles values(PAW); implementation of the  Vienna Ab initio Simulation Package insert ignore into journalissuearticles values(VASP);. The dependence of selected properties of this material on the  effective U parameter has been investigated in detail. We have used to examine structure parameter in  Fluoriteinsert ignore into journalissuearticles values(C1); structure of HfO2. The equilibrium geometries, the total and partial densities of states, elastic  constants, elastic moduli, Poisson’s ratio, Zener anisotropy factor, Young’s modulus and shear modulus and  phonon dispersion curves for this material are systematically investigated and analyzed in comparison with  experiments and previous calculations. We show for the first time that the addition of an on-site Hubbard  repulsion term to the LDA and GGA leads to improved agreement between calculated and experimental values  of structural and electronic properties, except for elastic properties.
Keywords : Hafnia, LDA U, GGA U, First principles calculation, mechanical properties, electronic structure, phonon dispersion