First principles prediction of the third conformer of hydrogenated BN sheet

We report, using first principles density functional calculations, the relative stabilities, structural and electronic properties of various conformers of hydrogenated BN sheet (BHNH). The already known chair and boat BHNH conformers are structurally similar to those of graphane. We propose a third BHNH conformer called 'stirrup' which turns out to be the most stable one, as also verified by frequency analysis. In this conformer, the B-H and N-H bonds of a hexagon alternate in 3-up and 3-down fashion on either side of the sheet. We also explore that any other alternative hydrogenation of the BN sheet disrupts its periodic puckered geometry and turns out to be energetically less stable. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)