Unexpected softness of bilayer graphene and softening of A-A stacked graphene layers

Sun, Yiwei; Holec, David; Gehringer, Dominik; Fenwick, Oliver; Dunstan, D. J.; Humphreys, C. J.

doi:10.1103/physrevb.101.125421

Cited by 10 publications

(8 citation statements)

References 32 publications

(44 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The unique atomic registry also results in an unexpected softness in the structure when subjected to compressive stress. [ 215 ] Upon out‐of‐plane compression, the π‐electron orbitals get squeezed out of the interlayer and started to interact with the in‐plane sp 2 electron, resulting in the unexpected softness in the AB or BA domains.…”

Section: Strain Engineering Of 2d Materials and Heterostructuresmentioning

confidence: 99%

Strain Engineering of Low‐Dimensional Materials for Emerging Quantum Phenomena and Functionalities

et al. 2022

View full text Add to dashboard Cite

Recent discoveries of exotic physical phenomena, such as unconventional superconductivity in magic‐angle twisted bilayer graphene, dissipationless Dirac fermions in topological insulators, and quantum spin liquids, have triggered tremendous interest in quantum materials. The macroscopic revelation of quantum mechanical effects in quantum materials is associated with strong electron–electron correlations in the lattice, particularly where materials have reduced dimensionality. Owing to the strong correlations and confined geometry, altering atomic spacing and crystal symmetry via strain has emerged as an effective and versatile pathway for perturbing the subtle equilibrium of quantum states. This review highlights recent advances in strain‐tunable quantum phenomena and functionalities, with particular focus on low‐dimensional quantum materials. Experimental strategies for strain engineering are first discussed in terms of heterogeneity and elastic reconfigurability of strain distribution. The nontrivial quantum properties of several strain‐quantum coupled platforms, including 2D van der Waals materials and heterostructures, topological insulators, superconducting oxides, and metal halide perovskites, are next outlined, with current challenges and future opportunities in quantum straintronics followed. Overall, strain engineering of quantum phenomena and functionalities is a rich field for fundamental research of many‐body interactions and holds substantial promise for next‐generation electronics capable of ultrafast, dissipationless, and secure information processing and communications.

show abstract

Section: Strain Engineering Of 2d Materials and Heterostructuresmentioning

confidence: 99%

Strain Engineering of Low‐Dimensional Materials for Emerging Quantum Phenomena and Functionalities

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The calculation setup was the same as in our previous work on graphite and bilayer graphene. [23] We modelled three layers of Bernal stacked graphene. We fixed the position of the bottom two layers and displaced the top layer towards the bottom two.…”

Section: B Dft Estimate Of Pressure Transmission In Dwcntsmentioning

confidence: 99%

Significant interlayer coupling in bilayer graphene and double-walled carbon nanotubes: A refinement of obtaining strain in low-dimensional materials

et al. 2022

Self Cite

View full text Add to dashboard Cite

This paper solves a longstanding debate: Raman measurements on double-walled carbon nanotubes appear to show that significantly more pressure than expected can be transmitted to the inner tube. We re-interpret those Raman spectra consistently reported in the literature, by assigning the Raman peaks to coupled vibrational modes of both walls, instead of individual contributions from the inner and outer tubes. These coupled vibrational modes are important for the correct interpretation of the Raman shift from strained layered 2D materials (we demonstrate it on bilayer graphene as an example), for researching the mechanical properties, thermal expansion and strain engineering of 2D materials.

show abstract

“…This softness is attributed to the squeezing of π-orbitals through the graphene plane in a bilayer system, whereas such squeezing-through is prohibited in graphite (infinite number of layers) by symmetry. 35 In addition to the compliance of the Pauli exclusion for undeformed π-orbitals, the other contribution from the graphene to the total compliance is from the deformation of the π-orbitals of the graphene. This could be estimated by calculating the energy difference between relaxed and deformed π-electron distributions.…”

Section: Out-of-plane Stiffness Of Graphenementioning

confidence: 99%

Mechanical properties of graphene

Sun

Papageorgiou

Humphreys

et al. 2021

Applied Physics Reviews

Self Cite

View full text Add to dashboard Cite

150Åand ethene at 1.33Å bond length) and smallest for triple-bonded carbon (acetylene, 1.20 151Å). On the other hand, the van der Waals (vdW) radius of a carbon atom is given as 1.70152Å . An early measurement of the thickness of the benzene molecule gave 4.70Å, 10 while the 153 thickness of the larger pyrene molecule is 3.53Å, 11 very close to the spacing of the graphene 154 sheets in graphite at 3.35Å.155 These considerations appear to give a clear meaning to the concept of the vdW thickness 156 of graphene, as much as of simpler molecules such as benzene and the higher polycyclic 157 aromatic compounds such as pyrene. It expresses the distance of closest approach of other 158 physisorbed atoms -whether carbon or anything else, because the repulsive interatomic 159 potential deriving from Pauli exclusion is largely independent of the nature of the interacting 160 atoms, and in the absence of a chemical bond, so is the vdW attractive potential. Following 161 Wyckoff, 9 the thickness should be expected to vary with the environment, whether it is a 162 surrounding gas or a substrate, as can be seen in Table I -even quite considerably as the 163 vdW forces, while always weak, can vary by an order of magnitude. 164 B. Graphene elastic stiffness tensor 165 Only in graphite is graphene found in a symmetrical environment (sandwiched between 166 graphene sheets with only a vdW potential binding them) and with a known thickness. We 167 may then define the graphene elastic stiffness constants c ij in this situation as a reference 168 system. To deal with possible variations in thickness in other environments, it makes sense

show abstract

Unexpected softness of bilayer graphene and softening of A-A stacked graphene layers

Cited by 10 publications

References 32 publications

Strain Engineering of Low‐Dimensional Materials for Emerging Quantum Phenomena and Functionalities

Strain Engineering of Low‐Dimensional Materials for Emerging Quantum Phenomena and Functionalities

Significant interlayer coupling in bilayer graphene and double-walled carbon nanotubes: A refinement of obtaining strain in low-dimensional materials

Mechanical properties of graphene

Contact Info

Product

Resources

About