First-principles study of wurtzite InN$(0001)$ and $(000{\bar 1})$ surfaces

TL;DR

This study uses density-functional calculations to identify the most stable atomic structures of wurtzite InN surfaces under different chemical conditions, revealing distinct surface reconstructions for N-rich and In-rich environments.

Contribution

First-principles calculations systematically determine stable surface structures of InN $(0001)$ and $(000{ar 1})$ surfaces under varying conditions, providing detailed atomic configurations.

Findings

Unreconstructed, In-terminated surface is stable under N-rich conditions.

A 3/4 monolayer of In atoms stabilizes the $(0001)$ surface under In-rich conditions.

The $(000{ar 1})$ surface favors a full monolayer of In atoms in atop sites.

Abstract

Density-functional calculations are used to study various plausible structures of the wurtzite InN $(0001)$ and $(000{\bar 1})$ surfaces. These structures include the unreconstructed surfaces, surfaces with monolayers of In or N, several possible coverages and locations of In or N adatoms and vacancies. The stable structure of the $(0001)$ surface under N-rich conditions is the unreconstructed, In-terminated, surface, while under In-rich conditions the stable surface has a 3/4 monolayer of In atoms. The stable structure of the InN $(000{\bar 1})$ surface corresponds to a full monolayer of In atoms in the atop sites (directly above the N atoms) over the entire range of accessible In (or N) chemical potential. The atomic structures of the low-energy structures are also discussed.