Phonon scattering at kinks in suspended graphene

Phonon scattering at kinks in suspended graphene

Dolleman, R.J. (TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft)
Blanter, Y.M. (TU Delft QN/Blanter Group; Kavli institute of nanoscience Delft)
van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft)
Steeneken, P.G. (TU Delft Dynamics of Micro and Nano Systems; TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft)
Verbiest, G.J. (TU Delft Dynamics of Micro and Nano Systems)

2020

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.

http://resolver.tudelft.nl/uuid:ef0e4f82-14b6-4746-b056-13dbcbeae573

https://doi.org/10.1103/PhysRevB.101.115411

2160-3308

Physical Review B, 101 (11)

Institutional Repository

journal article

© 2020 R.J. Dolleman, Y.M. Blanter, H.S.J. van der Zant, P.G. Steeneken, G.J. Verbiest