Selected Publications

A Graphene Resonator As An Ultrasound Detector For Generalized Love Waves In A Polymer Film With Two Level States

A. Laitinen, J.-P. Kaikkonen, T. S. Abhilash, I. Todoshchenko, J. Manninen, V. Zavyalov, A. Savin, A. Isacsson, P. J. Hakonen

We have investigated surface shear waves at 22 MHz in a 0.5 micron thick polymer film on a SiO2/Si substrate at low temperatures using suspended and non-suspended graphene as detectors. By tracking ultrasound modes detected by oscillations of a trilayer graphene membrane both in vacuum and in helium superfluid, we assign the resonances to surface shear modes, generalized Love waves, in the resist/silicon-substrate system loaded with gold. The propagation velocity of these shear modes displays a logarithmic temperature dependence below 1 K, which is characteristic for modification of the elastic properties of a disordered solid owing to a large density of two level state systems. For the dissipation of the shear mode, we find a striking logarithmic temperature dependence, which indicates a basic relation between the speed of the surface wave propagation and the mode dissipation.

Journal Of Physics D: Applied Physics 52, 24LT02 (2019)

doi: 10.1088/1361-6463/ab11a9