Topological Defects at the Graphene/h-BN interface Abnormally Enhance Its Thermal Conductance

Abstract

Low thermal conductance across interface is often the limiting factor in managing heat in many advanced device applications. The most commonly used approach to enhance the thermal conductance is to reduce/eliminate the interfacial structural defects. Using a graphene/h-BN (Gr/h-BN) interface, we show surprisingly that topological defects are able to enhance the thermal conductance across the interface. It is found that the phonon transmission across the Gr/h-BN interface with 5|7 defects is higher than that of the pristine interface, which is in strong contrast to the common notion that interface defects promote phonon scattering. By analyzing the strain distribution and phonon vibrational spectra, we find that this abnormal enhancement in interfacial thermal conductance originates from the localization of the stress fields arising from misfit dislocations and their out-of-plane deformations at the interface. In the presence of the defects, the overall mismatch strain is reduced. In addition, the out-of-plane deformations screen the long-ranged dislocation strain fields, resulting in the stress fields to be localized only at the cores of the defects. This abnormal mechanism provides a new dimension to enhance the interfacial thermal conductance in two-dimensional heterostructures.

Two-Dimensional Materials for Thermal Management Applications

“…98 Interfacial reinforcement can be achieved by stacking for more C-B matching to reduce interfacial space, 103 or specifically introducing 5j7 carbon defects to relax the lattice mismatch. 104 However, most work on this topic is based on computational methods and corresponding experimental investigations are urgently required.…”

Thermal Conductivity of Amorphous Materials

“…Consequently, this theory normally overestimates the ITR. Compared with the extensive studies on the ITR at interfaces between two crystalline materials, [126][127][128][129][130] the ITR at interfaces between amorphous materials is not well understood. One unexpected phenomenon contrary to intuition is that a larger interfacial thermal conductance at the interface between graphite and amorphous SiC compared to that at the interface of graphite and crystalline SiC was observed.…”

Unusual Twisting Phonons and Breathing Modes in Tube‐Terminated Phosphorene Nanoribbons and Their Effects on Thermal Conductivity

“…Edge often plays an important role in dictating the properties of 2D materials and their nanoribbons. So far, plenty of theoretical and experimental works have been devoted to study the thermal conductivity of graphene and MoS 2 nanoribbons, including the effects of nanoribbon size, edge roughness, substrate, and heterostructure . For a nanoribbon, its precise edge structure is often critically important for its thermal transport performance.…”