From graphene to graphane : A density functional investigation of metal insulator transition

TL;DR

This study uses density functional theory to investigate how hydrogenation induces a metal-insulator transition in graphene, revealing a complex evolution from semi-metal to metal and finally to insulator with increasing hydrogen coverage.

Contribution

It provides a detailed analysis of the electronic structure evolution in hydrogenated graphene, uncovering the inhomogeneous metallic phase and the transition pathway.

Findings

Hydrogenation causes graphene to transition from semi-metal to metal, then to insulator.

The metallic phase exhibits spatial inhomogeneity with insulating islands and metallic channels.

The transition depends on hydrogen concentration, with novel features uncovered.

Abstract

While graphene is a semi-metal, recently synthesized hydrogenated graphene called graphane, turns out to be an insulator. We have probed the metal insulator Transition in graphene-graphane system within the framework of density functional theory. By analysing the evolutionary trends in the electronic structure for fifteen different hydrogen concentrations on graphene, we unravel some novel features of this transition. As hydrogen coverage increases the semi-metal turns first into a metal, then transforms into an insulator. The metallic phase is spatially inhomogeneous in the sense, it contains the islands of insulating regions formed by hydrogenated carbon atoms and the metallic channels formed by contagious naked carbon atoms.