The third conformer of graphane: A first principles DFT based study

TL;DR

This study introduces a new stable conformer of graphane, named 'stirrup', characterized by a unique 3-up, 3-down hydrogen arrangement, with similar properties to known conformers, expanding understanding of graphane's structural diversity.

Contribution

First principles DFT calculations reveal a novel, stable 'stirrup' conformer of graphane with unique hydrogen arrangements and comparable stability to existing conformers.

Findings

The 'stirrup' conformer is energetically comparable to chair and boat conformers.

It exhibits an insulating direct band gap of 3.1 eV at the Gamma point.

Alternative hydrogenation patterns are less stable and disrupt symmetry.

Abstract

We propose, on the basis of our first principles density functional based calculations, a new isomer of graphane, in which the C-H bonds of a hexagon alternate in 3-up, 3-down fashion on either side of the sheet. This 2D puckered structure called 'stirrup' has got a comparable stability with the previously discovered chair and boat conformers of graphane. The physico-chemical properties of this third conformer are found to be similar to the other two conformers of graphane with an insulating direct band gap of 3.1 eV at the {\Gamma} point. Any other alternative hydrogenation of the graphene sheet disrupts its symmetric puckered geometry and turns out to be energetically less favorable.