Valence band photoemission from the GaN(0001) surface

TL;DR

This study uses one-step photoemission calculations to analyze the electronic structure of the GaN(0001) surface, confirming surface states and metallic bonds, and evaluating theoretical bulk band structures and experimental methods.

Contribution

It provides a detailed theoretical and experimental comparison to clarify the surface's structural and electronic properties, validating a proposed surface model and assessing valence band measurements.

Findings

Identification of surface states as fingerprints of the surface model

Confirmation of predicted metallic bonds on the surface

Support for one of two theoretical bulk band structures

Abstract

A detailed investigation by one-step photoemission calculations of the GaN(0001)-(1x1) surface in comparison with recent experiments is presented in order to clarify its structural properties and electronic structure. The discussion of normal and off-normal spectra reveals through the identified surface states clear fingerprints for the applicability of a surface model proposed by Smith et al. Especially the predicted metallic bonds are confirmed. In the context of direct transitions the calculated spectra allow to determine the valence band width and to argue in favor of one of two theoretical bulk band structures. Furthermore a commonly used experimental method to fix the valence band maximum is critically tested.