Electronic Structure of the Double Perovskite Ba2Er(Nb,Sb)O6

A V Gil Rebaza,D A Landínez Téllez,J Roa-Rojas,C E Deluque Toro

doi:10.1088/1742-6596/480/1/012041

Abstract

In this work, we present a detailed study of the structural and the electronic structure of the double perovskite Ba2Er(Nb,Sb)O6. All calculations were performed with the Full-Potential Linear Augmented Plane Wave method (FP-LAPW) based on the Density Functional Theory (DFT). From the minimization of energy as a function of volume using the Murnaghan's state equation has been obtained the equilibrium lattice parameter and the bulk modulus of these compounds. The study of the electronic structure was based in the analysis of the electronic density of states (DOS), and the density of charge, showing that these compounds have a total magnetic moment of 3.0 μB per formula unit due to Er atoms.

Highlights

The complex perovskites with generic formula A2MM'O6 [1,2,3] have been subject of enhanced scientific studies because the wide range of applications that these materials present on an industrial scale, double perovskites belonging to the series Ba2LnB'O6 (Ln=lanthanide and Y3+ and B'=Nb5+, Ta5+, Sb5+) are of interest due to their potential use as substrates for high-Tc superconductors [4,5] and their likely high chemical compatibility with the structurally analogous, oxygen deficient double perovskites, Ba2LnSnO6-δ; a series of interest for use as solid state electrolytes due to their high ionic conductivity [6,7]
In order to obtain the equilibrium structure, the total energy vs. lattice parameter curves were obtained for BaEr(Nb,Sb)O compounds using Local Spin Density Approximation (LSDA) and Generalized Gradient Approximation (GGA)
These curves were fitted using the Birch-Murnaghan’s state equation [18] to determine the equilibrium lattice parameters (a), bulk modulus (B) and their derivate (B’). We shows these values together experimental data obtained from the bibliography [11,12,13]. For both compounds the ground state belong to GGA calculations, where the a value for these compounds are in agree with experimental one

Summary

Introduction

The complex perovskites with generic formula A2MM'O6 [1,2,3] have been subject of enhanced scientific studies because the wide range of applications that these materials present on an industrial scale, double perovskites belonging to the series Ba2LnB'O6 (Ln=lanthanide and Y3+ and B'=Nb5+, Ta5+, Sb5+) are of interest due to their potential use as substrates for high-Tc superconductors [4,5] and their likely high chemical compatibility with the structurally analogous, oxygen deficient double perovskites, Ba2LnSnO6-δ; a series of interest for use as solid state electrolytes due to their high ionic conductivity [6,7]. Previous studies [9, 10], using laboratory X-ray and medium resolution neutron diffraction, reported that the structures in the series Ba2LnSbO6 change from R-3 rhombohedral (tilt system a-a-a-) to Fm3m cubic (a0a0a0) symmetry with decreasing size of the Ln3+ cation. An increase in the tolerance factor indicates that the volume of the BO6 octahedron is better matched to the size of the AO12 polyhedron reducing the need for the octahedral tilting to accommodate this A-site cation.

Objectives

Results

Conclusion