The effect of torsional deformation on thermal conductivity of mono-, bi- and trilayer graphene nanoribbon

• Thermal conductivity of graphene nanoribbons is calculated using a nonequilibrium molecular dynamics method.
• Twist effect on the thermal conductivity of mono-, bi-, and trilayer graphene is investigated.
• As twist increases the thermal conductivity decreases, but depends upon both temperature and aspect ratio.
• Phonon dispersion curve and phonon density of states of twisted GNR are evaluated.
• Reduced thermal conductivity of twisted GNR is due to the phonon softening of acoustic phonon modes.

Physical deformation and geometrical change of a low dimensional nanostructure influence the phonon transport leading to appreciable changes in the thermal characteristics. In this paper, we report the calculation of the thermal conductivity of twisted graphene nanoribbon (GNR) using nonequilibrium molecular dynamics (NEMD). A reduction in the value of thermal conductivity of GNR is observed with an increase in the angle of twist. It is observed that the value of thermal conductivity of twisted GNR is dependent on the length of GNR and the temperature at which physical deformation is taking place. Comparing with monolayer GNR, the reduction in the thermal conductivity of bilayer and trilayer GNR is less due to the interactions between the adjacent layers. Analysis of the phonon transport in twisted graphene implies that the reduced thermal conductivity of twisted graphene nanoribbon is due to the phonon softening of acoustic phonon modes.