Unexpected Thermal Conductivity Enhancement in Pillared Graphene Nanoribbon with Isotopic Resonance

TL;DR

This study reveals that isotope engineering can unexpectedly enhance thermal conductivity in pillared graphene nanoribbons by disrupting resonant hybridization wave effects, offering new ways to control heat transport in nanostructures.

Contribution

It demonstrates a novel mechanism where isotope engineering increases thermal conductivity by breaking resonant wave hybridization in phononic metamaterials.

Findings

Isotope engineering can enhance thermal conductivity in GNPM.

Breaking resonant hybridization wave effects increases heat conduction.

System width and pillar height effectively tune thermal transport.

Abstract

Thermal transport in nanoribbon based nanostructures is critical to advancing its applications. Wave effects of phonons can give rise to controllability of heat conduction in nanostructures beyond that by particle scattering. In this paper, by introducing pillars to form structural resonance, we systematically studied the thermal conductivity of graphene nanoribbon based phononic metamaterials (GNPM) through non-equilibrium molecular dynamical simulation. Interestingly, it is found that the thermal conductivity of GNPM is counter intuitively enhanced by isotope engineering, which is strong contrast to the common notion that isotope engineering reduces thermal conductivity.Further mode analysis and atomic Green function calculation reveal that the unexpected increasing in thermal conductivity originates from the breaking of the resonant hybridization wave effect between the resonant modes and the propagating modes induced by isotope engineering. Besides, factors including the system width and pillar height can also efficiently tune the thermal conductivity of GNPM. This abnormal mechanism provides a new dimension to manipulate phonon transport in nanoribbon based nanostructures through wave effect.