Density-functional study of the structure and stability of ZnO surfaces

TL;DR

This study uses density functional theory to analyze the structure and stability of various ZnO surfaces, focusing on convergence issues and comparing results with prior data.

Contribution

It provides a comprehensive theoretical analysis of ZnO surface structures and stability, addressing convergence and methodological issues with detailed comparisons.

Findings

Structural relaxations and energetics are reliably calculated.

Different approaches to polar surface stability are evaluated.

Results are consistent with and expand upon previous theoretical and experimental data.

Abstract

An extensive theoretical investigation of the nonpolar (10$\bar{1}$0) and (11$\bar{2}$0) surfaces as well as the polar zinc terminated (0001)--Zn and oxygen terminated (000$\bar{1}$)--O surfaces of ZnO is presented. Particular attention is given to the convergence properties of various parameters such as basis set, k--point mesh, slab thickness, or relaxation constraints within LDA and PBE pseudopotential calculations using both plane wave and mixed basis sets. The pros and cons of different approaches to deal with the stability problem of the polar surfaces are discussed. Reliable results for the structural relaxations and the energetics of these surfaces are presented and compared to previous theoretical and experimental data, which are also concisely reviewed and commented.