Density Functional Theory (DFT) Study of Electronic and Structural Properties in Dy-Doped YBa2Cu3O7 Superconductors

Abstract

The impact of Dy doping at the Y-site of the Y_1-xDy_xBa₂Cu₃O_7-δ superconductor on its electronic properties was examined using Density Functional Theory (DFT) through a first-principles study. Computational simulations were performed utilizing the CASTEP computational code. The crystal structure was modelled and calculated with the Visual Crystal Approximation (VCA) employing the Generalized Gradient Approximation Perdew-Burke-Ernzerhof for Solids (GGA PBEsol) exchange-correlation and ultrasoft pseudopotential. Band structure analysis revealed the smallest bandgap at x = 0.15 between the conduction band (CB) and the valence band (VB). Electron density was found to be more concentrated near the Fermi level based on the density of states distribution. Electron density difference images displayed the merging of orbital configurations from each atom upon doping at x = 0.15. This indicates that at this specific Dy concentration, Y_1-xDy_xBa₂Cu₃O_7-δ achieves the optimal properties.