Phonon scattering at kinks in suspended graphene
Robin Joey Dolleman (Kavli institute of nanoscience Delft, TU Delft - Applied Sciences)
Yaroslav Blanter (Kavli institute of nanoscience Delft, TU Delft - Applied Sciences)
Herre van der Zant (TU Delft - Applied Sciences, Kavli institute of nanoscience Delft)
Peter Steeneken (TU Delft - Applied Sciences, Kavli institute of nanoscience Delft, TU Delft - Mechanical Engineering)
Gerard Verbiest (TU Delft - Mechanical Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Recent experiments have shown surprisingly large thermal time constants in suspended graphene ranging from 10 to 100 ns in drums with a diameter ranging from 2 to 7 μm. The large time constants and their scaling with diameter points toward a thermal resistance at the edge of the drum. However, an explanation of the microscopic origin of this resistance is lacking. Here, we show how phonon scattering at a kink in the graphene, e.g., formed by sidewall adhesion at the edge of the suspended membrane, can cause a large thermal time constant. This kink strongly limits the fraction of flexural phonons that cross the suspended graphene edge, which causes a thermal resistance at its boundary. Our model predicts thermal time constants that are of the same order of magnitude as experimental data and shows a similar dependence on the circumference. Furthermore, the model predicts the relative in-plane and out-of-plane phonon contributions to graphene's thermal expansion force, in agreement with experiments. We thus show an unconventional thermal boundary resistance which occurs solely due to strong deformations within a two-dimensional material.