Quantifying superlubricity of bilayer graphene from the mobility of interface dislocations

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Main Authors: Ahmed, Md Tusher, Choi, Moon-ki, Johnson, Harley T, Admal, Nikhil Chandra
Format: Preprint
Published: 2025
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author Ahmed, Md Tusher
Choi, Moon-ki
Johnson, Harley T
Admal, Nikhil Chandra
author_facet Ahmed, Md Tusher
Choi, Moon-ki
Johnson, Harley T
Admal, Nikhil Chandra
contents Van der Waals (vdW) heterostructures subjected to interlayer twists or heterostrains demonstrate structural superlubricity, leading to their potential use as superlubricants in micro- and nano-electro-mechanical devices. However, quantifying superlubricity across the vast four-dimensional heterodeformation space using experiments or atomic-scale simulations is a challenging task. In this work, we develop an atomically informed dynamic Frenkel--Kontorova (DFK) model for predicting the interface friction drag coefficient of an arbitrarily heterodeformed bilayer graphene (BG) system. The model is motivated by MD simulations of friction in heterodeformed BG. In particular, we note that interface dislocations formed during structural relaxation translate in unison when a heterodeformed BG is subjected to shear traction, leading us to the hypothesis that the kinetic properties of interface dislocations determine the friction drag coefficient of the interface. The constitutive law of the DFK model comprises the generalized stacking fault energy of the AB stacking, a scalar displacement drag coefficient, and the elastic properties of graphene, which are all obtained from atomistic simulations. Simulations of the DFK model confirm our hypothesis since a single choice of the displacement drag coefficient, fit to the kinetic property of an individual dislocation in an atomistic simulation, predicts interface friction in any heterodeformed BG. By bridging the gap between dislocation kinetics at the microscale to interface friction at the macroscale, the DFK model enables a high-throughput investigation of strain-engineered vdW heterostructures.
format Preprint
id arxiv_https___arxiv_org_abs_2501_05328
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantifying superlubricity of bilayer graphene from the mobility of interface dislocations
Ahmed, Md Tusher
Choi, Moon-ki
Johnson, Harley T
Admal, Nikhil Chandra
Mesoscale and Nanoscale Physics
Van der Waals (vdW) heterostructures subjected to interlayer twists or heterostrains demonstrate structural superlubricity, leading to their potential use as superlubricants in micro- and nano-electro-mechanical devices. However, quantifying superlubricity across the vast four-dimensional heterodeformation space using experiments or atomic-scale simulations is a challenging task. In this work, we develop an atomically informed dynamic Frenkel--Kontorova (DFK) model for predicting the interface friction drag coefficient of an arbitrarily heterodeformed bilayer graphene (BG) system. The model is motivated by MD simulations of friction in heterodeformed BG. In particular, we note that interface dislocations formed during structural relaxation translate in unison when a heterodeformed BG is subjected to shear traction, leading us to the hypothesis that the kinetic properties of interface dislocations determine the friction drag coefficient of the interface. The constitutive law of the DFK model comprises the generalized stacking fault energy of the AB stacking, a scalar displacement drag coefficient, and the elastic properties of graphene, which are all obtained from atomistic simulations. Simulations of the DFK model confirm our hypothesis since a single choice of the displacement drag coefficient, fit to the kinetic property of an individual dislocation in an atomistic simulation, predicts interface friction in any heterodeformed BG. By bridging the gap between dislocation kinetics at the microscale to interface friction at the macroscale, the DFK model enables a high-throughput investigation of strain-engineered vdW heterostructures.
title Quantifying superlubricity of bilayer graphene from the mobility of interface dislocations
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2501.05328