Intrinsic Negative Poisson’s Ratio for Single-Layer Graphene

Abstract

Negative Poisson's ratio (NPR) materials have drawn significant interest because the enhanced toughness, shear resistance and vibration absorption that typically are seen in auxetic materials may enable a range of novel applications. In this work, we report that single-layer graphene exhibits an intrinsic NPR, which is robust and independent of its size and temperature. The NPR arises due to the interplay between two intrinsic deformation pathways (one with positive Poisson's ratio, the other with NPR), which correspond to the bond stretching and angle bending interactions in graphene. We propose an energy-based deformation pathway criteria, which predicts that the pathway with NPR has lower energy and thus becomes the dominant deformation mode when graphene is stretched by a strain above 6%, resulting in the NPR phenomenon.

The normal-auxeticity mechanical phase transition in graphene

“…It shows that ν decreases from around 0.21 to −0.03 when strain ε x increases from 0% to 10%. In comparison with the data reported in [7], a noticeable discrepancy exists at equilibrium (zero strain) in which ν was reported to be about 0.31. Considering the first principle calculation of monolayer graphene in our previous work [29] in which ν was calculated to be about 0.18, the authors might have significantly overestimated ν at the initial stage of the tensile test.…”

“…The black curve is the reproduced data of [7] for comparison. It clearly shows that the red curve overlaps the black one up to 10% strain in the armchair direction.…”

“…With a high carrier mobility and saturation velocity, graphene has promising applications in ultrahigh-speed radiofrequency electronics [4][5][6]. Monolayer pristine graphene has been recently reported to exhibit intrinsic positive Poisson's ratio (PPR) to negative Poisson's ratio (NPR) transition behavior [7] via molecular dynamics simulations [8]. The unique phenomenon of the normal-auxeticity (NA) transition occurs when a monolayer graphene reaches an engineering strain of about 6% in the armchair direction, or the nearest neighbor direction.…”

A perspective on auxetic nanomaterials

“…However, very few reports of in-plane NPR have emerged. For example, transition metal dichalcogenides MX 2 (MoSe 2 , MoTe 2 , WSe 2 , WTe 2 , TcTe 2 , ReSe 2 , and ReTe 2 ) shows in-plane auxeticity in the elastic range [40], and pristine graphene [41] and semi-fluorinated graphene [42] exhibit in-plane auxeticity for large tensile strains exceeding about 6 and 9%, respectively.…”

Negative In‐Plane Poisson's Ratio for Single Layer Black Phosphorus: An Atomistic Simulation Study

“…Surface effect in metal nanoplates and nanowires, edge effect in graphene ribbons, and puckered crystal structure of single layer black phosphorus (SLBP) are some typical examples of the intrinsic mechanisms for auxeticity for nanoscale materials. Jiang et al used molecular dynamics (MD) simulations with the second‐generation Reactive Empirical Bond Order (REBO‐II) potential to show that pristine graphene can exhibit a NPR when the applied strain exceeds 0.06 . They have also shown that the interplay between the bond stretching and bond rotating modes are the origin for the auxeticity in the pristine graphene.…”