Twist the sheet and its wrinkles throttle heat flow.
Graphene, h-BN, and MoS₂ all lose conductivity under torsion. Wrinkle height gives the comparison a physical scale, and its square captures the reported conductivity trend.
Materials Today Communications · 2020 · S Arabha, A Rajabpour
Deformation changes the path for lattice vibrations
Heat in atomically thin sheets is carried by lattice vibrations. Twisting a sheet creates wrinkles that disturb those vibrations, but different 2D materials need not respond equally.
How much does torsional deformation reduce heat transport in graphene, hexagonal boron nitride, and MoS₂, and does wrinkle amplitude explain the change?
Twist a ring and follow the heat
The study used non-equilibrium molecular dynamics to twist monolayer and few-layer sheets, compare thermal conductivity at different torsional strains and inner radii, and relate conductivity loss to wrinkle geometry and vibrational spectra.
Non-equilibrium molecular dynamics calculates radial heat flow through ring-shaped graphene, h-BN, and MoS₂ sheets. The inner boundary is twisted while the outer boundary constrains the structure. Results are normalized by each material’s pristine conductivity, making the fractional response visible despite very different starting conductivities. The authors stress that these small specimens support a qualitative deformation study; their finite-size conductivities are not macroscopic material constants.
Key findings
From torsion to shape
A 5° rotation reorganizes the height field, with material-dependent amplitude and a finite failure limit.
Thermal sensitivity
Normalized conductivity exposes deformation sensitivity rather than the differences in starting conductivity.
Microscopic mechanism
The vibrational spectrum and geometry comparisons connect deformed shape with the reduced heat-flow response.
Include the deformed shape in the thermal picture
Torsion provides a way to tune thermal transport, but the reduction depends on both the wrinkle pattern and the material’s vibrational response.
The findings are useful for interpreting heat transport in mechanically loaded 2D sheets. A conductivity assigned to a flat sheet can change once torsion and wrinkles become part of the structure.