Local strain effect on the thermal transport of graphene nanoribbons: a molecular dynamics investigation.

Abstract

Strain engineering of the thermal conductivity of graphene is highly desirable for various nanoscale thermal devices. Previous investigations have been focused mainly on the uniform strain applied uniaxially or biaxially. In this work we investigated, by non-equilibrium molecular dynamics simulations, the thermal transport behavior of graphene nanoribbons under local, nonuniform strain. A capped carbon nanotube (CNT) is used as a representative tip to indent the graphene, which creates a local stress field similar to those induced by nanoindentation or molecular adsorption. The relationship among structural deformations, phonon transport, and stress field was analyzed, and the effects of indentation depth and tip-surface interaction strength were discussed. More than 50% reduction of thermal conductance can be observed for a 20 nm × 5 nm graphene nanoribbon upon indentation. Our study revealed that the thermal transport of graphene responds flexibly and sensitively to the local strain, which can be exploited for new functional nanodevices across various disciplines such as position sensing or molecular sensing. Thermal sensors based on graphene can then be constructed.