Novel Two-Dimensional Silica Monolayers with Tetrahedral and Octahedral Configurations

Abstract

Free-standing and well-ordered two-dimensional (2D) silica monolayers with tetrahedral (T-silica) and octahedral (O-silica) building blocks are found to be stable by first principles calculations; T-silica is formed by corner-sharing SiO 4 tetrahedrons in a rectangular network and O-silica consists of edge-sharing SiO 6 octahedrons.Moreover, the insulating O-silica is the strongest silica monolayer, and can therefore act as a supporting substrate for nanostructures in sensing and catalytic applications.Nanoribbons of T-silica are metallic while those of O-silica have band gaps regardless of the chirality. We find the interaction of O-silica with graphene to be weak suggesting the possibility of its use as a monolayer dielectric material for graphene-based devices. Considering that the six-fold coordinated silica exists at high pressure in the bulk phase, the prediction of a small energy difference of O-silica with the synthesized silica bilayer together with the thermal stability at 1000 K suggest that synthesis of O-silica can be achieved in experiments.

Graphene-like monolayer monoxides and monochlorides

“…1E and SI Appendix, Fig. S3, based on the Tersoff and Hamann approximation (18) at constant height mode used to mimic the experimental setup (19). The simulated STM images of 2D NaCl, MgO, LiCl, and SrO monolayers show the symmetrical honeycomb structure, which is similar to the structure of graphene.…”

Supramolecular chemistry under mechanochemical conditions: a small molecule template generated and integrated into a molecular-to-supramolecular and back-to-molecular cascade reaction

“…The angular nature of the bridges means that the topology of the grid 2(dat)$(4,4 0 -tpcb) conforms to T-silica, which is a recently calculated and metastable form of SiO 2 . 31 We are unaware of a molecular network that conforms to the topology of T-silica.…”

Frequency thermal response and cooling performance in a microscopic system with a time-dependent perturbation

“…Therefore our model can describe composite systems on substrates that can be realized by linear lattices with static pinning potentials. Examples of such systems are polymeric polar chains where the opening or locking of phonon channels can be adjusted under the action of electric fields and composed short alkane chains o molecular junctions that can be stretched or pulled under some defined protocol [29,30,31].…”