Ab initio calculations of CaZrO3 (011) surfaces: systematic trends in polar (011) surface calculations of ABO3 perovskites

Roberts I Eglitis,J Kleperis,Ran Jia,A I Popov,J Purans

doi:10.1007/s10853-019-04016-3

Roberts I Eglitis, J Kleperis + Show 3 more

Open Access

https://doi.org/10.1007/s10853-019-04016-3

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Abstract

By means of the CRYSTAL computer program package, first-principles calculations of polar ZrO-, Ca- and O-terminated CaZrO3 (011) surfaces were performed. Our calculation results for polar CaZrO3 (011) surfaces are compared with the previous ab initio calculation results for ABO3 perovskite (011) and (001) surfaces. From the results of our hybrid B3LYP calculations, all upper-layer atoms on the ZrO-, Ca- and O-terminated CaZrO3 (011) surfaces relax inwards. The only exception from this systematic trend is outward relaxation of the oxygen atom on the ZrO-terminated CaZrO3 (011) surface. Different ZrO, Ca and O terminations of the CaZrO3 (011) surface lead to a quite different surface energies of 3.46, 1.49, and 2.08 eV. Our calculations predict a considerable increase in the Zr–O chemical bond covalency near the CaZrO3 (011) surface, both in the directions perpendicular to the surface (0.240e) as well as in the plane (0.138e), as compared to the CaZrO3 (001) surface (0.102e) and to the bulk (0.086e). Such increase in the B–O chemical bond population from the bulk towards the (001) and especially (011) surfaces is a systematic trend in all our eight calculated ABO3 perovskites.

Highlights

The neutral (001) as well as polar and charged (011) surfaces of the ABO3 perovskites are both of fundamental interest for basic research, and very important for practical applications, for example, numerous microelectronic, catalytic, and other high-technology applications as well as they are frequently used as substrates for growth of other materials such as cuprate superconductors [28,29,30,31,32,33,34]
Our previous calculation results for CaTiO3, SrTiO3, PbTiO3, BaTiO3, SrZrO3, PbZrO3 and BaZrO3 (011) surfaces performed by B3LYP [71] or B3PW [73] functional are listed for comparison purpose with aim to detect systematic trends in polar (011) surface calculations for all eight technologically most important ABO3 perovskites
The only exception is outward relaxation of ZrO-terminated CaZrO3 (011) surface upper-layer O atom by 4.96% of the bulk lattice constant a0

Summary

Introduction

Surface and interface phenomena, taking place in the ABO3 perovskites and their nanostructures, as well as mechanisms of various (001) and (011) surface electronic processes, are the key topics in theoretical solid-state physics [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]. Our previous calculation results for CaTiO3, SrTiO3, PbTiO3, BaTiO3, SrZrO3, PbZrO3 and BaZrO3 (011) surfaces performed by B3LYP [71] or B3PW [73] functional are listed for comparison purpose with aim to detect systematic trends in polar (011) surface calculations for all eight technologically most important ABO3 perovskites.

Results

Conclusion