Configuration- and concentration-dependent electronic properties of hydrogenated graphene

TL;DR

This study uses first-principles calculations to explore how hydrogen configuration and concentration affect the electronic properties of hydrogenated graphene, revealing tunable band gaps and diverse electronic features.

Contribution

It provides a comprehensive analysis of the relationship between hydrogen adatom arrangements and the resulting electronic properties of graphene, highlighting the tunability of band gaps.

Findings

Band gaps can be modulated in zigzag hydrogenated graphene systems.

Diverse electronic features including Dirac cone destruction and flat bands.

Charge distributions link bonding configurations to electronic properties.

Abstract

The electronic properties of hydrogenated graphenes are investigated with the first-principles calculations. Geometric structures, energy bands, charge distributions, and density of states (DOS) strongly depend on the different configurations and concentrations of hydrogen adatoms. Among three types of optimized periodical configurations, only in the zigzag systems the band gaps can be remarkably modulated by H-concentrations. There exist middle-gap semiconductors, narrow-gap semiconductors, and gapless systems. The band structures exhibit the rich features, including the destruction or recovery of the Dirac-cone structure, newly formed critical points, weakly dispersive bands, and (C,H)-related partially flat bands. The orbital-projected DOS are evidenced by the low-energy prominent peaks, delta-function-like peaks, discontinuous shoulders, and logarithmically divergent peaks. The DOS and spatial charge distributions clearly indicate that the critical bondings in C-C and C-H is responsible for the diversified properties.