Diversified essential properties in halogenated graphenes

TL;DR

This study uses first-principles calculations to explore how different halogenations alter the structure, electronic, and magnetic properties of graphene, revealing diverse behaviors including metallicity, semiconducting states, and ferromagnetism.

Contribution

It provides a comprehensive analysis of the effects of various halogen adatoms on graphene's properties, highlighting new structural and electronic phenomena induced by halogenation.

Findings

Fluorination creates buckled graphene structures.

Most halogenated graphene systems are hole-doped metals.

Certain adatom arrangements induce metallic ferromagnetism.

Abstract

The significant halogenation effects on the essential properties of graphene are investigated by the first-principles method. The geometric structures, electronic properties, and magnetic configurations are greatly diversified under the various halogen adsorptions. Fluorination, with the strong multi-orbital chemical bondings, can create the buckled graphene structure, while the other halogenations do not change the planar {\sigma} bonding in the presence of single-orbital hybridization. Electronic structures consist of the carbon-, adatom- and (carbon, adatom)-dominated energy bands. All halogenated graphenes belong to hole-doped metals except that fluorinated systems are middle-gap semiconductors at sufficiently high concentration. Moreover, the metallic ferromagnetism is revealed in certain adatom distributions. The unusual hybridization-induced features are clearly evidenced in many van Hove singularities of the density of states. The structure- and adatom-enriched essential properties are compared with the measured results, and potential applications are also discussed.