Bending Rigidity of 2D Silica

Abstract

A chemically stable bilayers of SiO_{2} (2D silica) is a new, wide band gap 2D material. Up till now graphene has been the only 2D material where the bending rigidity has been measured. Here we present inelastic helium atom scattering data from 2D silica on Ru(0001) and extract the first bending rigidity, κ, measurements for a nonmonoatomic 2D material of definable thickness. We find a value of κ=8.8 eV±0.5 eV which is of the same order of magnitude as theoretical values in the literature for freestanding crystalline 2D silica.

Material properties particularly suited to be measured with helium scattering: selected examples from 2D materials, van der Waals heterostructures, glassy materials, catalytic substrates, topological insulators and superconducting radio frequency materials

“…30 HAS was recently used to obtain also the bending rigidity and coupling strength of a 2D silica bilayer weakly bound on Ru. 31 Furthermore the bending rigidity and coupling strength of graphene on sapphire 32 have been measured. The latter experiment illustrates how the defect density affects the bending rigidity of the graphene.…”

The electron–phonon coupling constant for single-layer graphene on metal substrates determined from He atom scattering

“…It is eqn ( 10) that has been used to determine the bending rigidity k of the ZA mode of graphene supported by the metals considered here [4][5][6][7][8] as well as for the thinnest known layer of vitreous glass, a bilayer of SiO 2 on Ru(0001). 78 It is important to note that most of the modelling of supported graphene dynamics is based on the assumption of a rigid substrate. However, the phonon spectrum of graphene, with its large dispersion of acoustic modes and high-frequency optical modes, covers the whole phonon spectrum of the substrate, and therefore several avoided crossings are expected between graphene and the substrate modes of similar polarization.…”

“…6,[79][80][81][82][83] This also appears in the case of other thin film materials such as bilayer SiO 2 . 78,84 The study of the dynamics of elastic plates dates back to works of Euler, Bernoulli, D'Alembert, Sophie Germain and Lagrange, just to mention some of the pioneers, and the terminology is well established. 85 When transferred to lattice dynamics, transverse modes refer to lattices with cyclic (or fixed) boundary conditions, whereas flexural modes refer to lattices with free boundaries.…”

Growth and Atomic‐Scale Characterization of Ultrathin Silica and Germania Films: The Crucial Role of the Metal Support

“…The silica bilayer today is in the tool box of 2D materials, [76] thanks to extensive characterization that includes studies of: work function, [77] band‐gap, [78] crystalline‐vitreous interface, [3] atomic [9, 11] and molecular [79, 11, 80] sieve, confined chemistry, [59, 12, 60, 61] bending rigidity, [81] 2D zeolites, [82–84] transferring from one substrate to another [6] and imaging in water [85] . With all this knowledge available, the silica bilayer becomes an interesting dielectric material for nanoelectronic devices [76]…”