Chair and Twist-Boat Membranes in Hydrogenated Graphene

Samarakoon, Duminda K.; Wang, Xiaoqian

doi:10.1021/nn901317d

Cited by 93 publications

(114 citation statements)

References 27 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…The literature contains calculations of the electronic structure of single graphane sheets (5,(21)(22)(23)(24), and of extended structures built from them (21,23), all consistent with insulating or semiconducting behavior. Though normal DFT calculations, such as Scheme 2.…”

Section: Why the Change In Preferred Structure With Pressure?mentioning

confidence: 99%

See 1 more Smart Citation

Graphane sheets and crystals under pressure

Wen

Hand

Labet

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

135

162

View full text Add to dashboard Cite

Eight isomeric two-dimensional graphane sheets are found in a theoretical study. Four of these nets-two built on chair cyclohexanes, two on boat-are more stable thermodynamically than the isomeric benzene, or polyacetylene. Three-dimensional crystals are built up from the two-dimensional sheets, and their hypothetical behavior under pressure (up to 300 GPa) is explored. While the three-dimensional graphanes remain, as expected, insulating or semiconducting in this pressure range, there is a remarkable inversion in stability of the five crystals studied. Two stacking polytypes that are not the most stable at ambient pressure (one based on an unusual chair cyclohexane net, the other on a boat) are significantly stabilized with increasing pressure relative to stackings of simple chair sheets. The explanation may lie in the balance on intra and intersheet contacts in the extended arrays. Our interest in the field developed from another direction. We have been studying theoretically benzene (C 6 H 6 ) under high pressure. The stoichiometry of the material is, of course, the same as that of graphane. In our calculations we first found that benzene phases under pressure underwent (at a certain pressure) phase transformation to saturated CH structures that were more stable. Among these more stable structures were graphanes. We report here the three-dimensional saturated CH graphane structures, some unique, that emerge from our theoretical work, and their computed behavior under pressure.Results and Discussion CH Structures from Evolutionary Structure Predictions. Once we found some saturated CH structures that were more stable than benzene, we began to look for more of them by evolutionary algorithm structure prediction, using the USPEX method/code (15-17) over the range of 0 to 300 GPa.Five graphane stackings emerged as low in enthalpy at one or another pressure. These multilayer graphane structures are shown in Fig. 1. We call them:• graphane I (space group P-3m1, Z ¼ 2, i.e., 2 CH in the unit cell, -AA-stacking),Note that just as for graphite, diamond, and SiC, there are many potential stacking polytypes built on any component sheet, e.g., -ABC-, -AABB-stacking and so on. These stackings were not explored by us; all of them are likely to be of similar enthalpy at ambient pressure to these five structures.

show abstract

Section: Why the Change In Preferred Structure With Pressure?mentioning

confidence: 99%

“…The chair2 layer, B, occurs also (not for carbon, and not as an isolated layer) in hundreds of inorganic compounds, such as BaIn 2 (18), TiNiSi (19), or EuAuSn (20). Layer B for graphane has also been suggested in the literature by several researchers (4,(21)(22)(23)(24). Also Layer D, boat2, has been forwarded by Leenaerts et al (22).…”

mentioning

confidence: 93%

Graphane sheets and crystals under pressure

Wen

Hand

Labet

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

135

162

View full text Add to dashboard Cite

show abstract

“…The diatropic current of the dihydropyrene (5) is readily rationalized in terms of the analogy with a delocalized C 2h -constrained [14] annulene, and again arises essentially from node-increasing excitations between Λ = 3 HOMO and Λ = 4 LUMO pairs, each of which is split into two components under C 2h symmetry.…”

Section: Diatropic and Paratropic Currents In Nanographanesmentioning

confidence: 99%

Writing with ring currents: selectively hydrogenated polycyclic aromatics as finite models of graphene and graphane

2014

View full text Add to dashboard Cite

Alternating partial hydrogenation of the interior region of a polycyclic aromatic hydrocarbon gives a finite model system representing systems on the pathway from graphene to the graphane modification of the graphene sheet. Calculations at the DFT and coupled Hartree–Fock levels confirm that sp 2 cycles of bare carbon centres isolated by selective hydrogenation retain the essentially planar geometry and electron delocalization of the annulene that they mimic. Delocalization is diagnosed by the presence of ring currents, as detected by ipsocentric calculation and visualization of the current density induced in the π system by a perpendicular external magnetic field. These induced ‘ring’ currents have essentially the same sense, strength and orbital origin as in the free hydrocarbon. Subjected to the important experimental proviso of the need for atomic-scale control of hydrogenation, this finding predicts the possibility of writing single, multiple and concentric diatropic and/or paratropic ring currents on the graphene/graphane sheet. The implication is that pathways for free flow of ballistic current can be modelled in the same way.

show abstract

“…Researchers modied several graphene based materials among them the hydrogenated graphene (called graphane). [12][13][14][15][16][17][18][19] In 2003, Sluiter and Kawazoe…”

Section: Introductionmentioning

confidence: 99%

“…These band gaps and also the calculated Young's moduli are at variance with available experimental data. Duminda et al 21 have studied the stability of chair, boat, and twist-boat graphane structures using rst-principles calculations. Their results indicate that locally stable twist-boat membranes signicantly contribute to the experimentally observed lattice contraction.…”

mentioning

confidence: 99%

Electronic and optical properties of chair-like and boat-like graphane

Reshak

Auluck

2014

RSC Adv.

View full text Add to dashboard Cite

We have studied two favorable conformations of graphane, the chair-like graphane and boat-like graphane. In the chair-like, the H atoms attached to the C atoms alternate on both sides of the sheet while in the boatlike, the C bonded H atoms alternate in pair. Both conformations of graphane have a 2D puckered honeycomb like structure with one hydrogen atom bonded covalently (sp 3 ) to each carbon atom. The chair-like belongs to the P 3m1 (164)

show abstract

Chair and Twist-Boat Membranes in Hydrogenated Graphene

Cited by 93 publications

References 27 publications

Graphane sheets and crystals under pressure

Graphane sheets and crystals under pressure

Writing with ring currents: selectively hydrogenated polycyclic aromatics as finite models of graphene and graphane

Electronic and optical properties of chair-like and boat-like graphane

Contact Info

Product

Resources

About