Phonon propagation in a topological non-trivial phononic waveguide
O.R. Ranjbar-Neini1, G. Conte1, M. Balagopalan1, M.D. Koijam2, Y. Pennec2, B. Djafari-Rouhani2, O. Ylivaara3, S. Pourjamal3, T. Makkonen3, J. Ahopelto3 and C.M. Sotomayor Torres1
1 International Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal.
2 IEMN (UMR CNRS 8520), University of Lille, Lille 59650, France.
3 VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Espoo, Finland.
In the quest for a token of information which is fundamentally one using low power, we homed in phonons for interconnects.
In this context we report recent studies of topological non-trivial phononic interface waveguides in silicon at room temperature. The nanocrystalline silicon (nc-Si) structures are based on phononic band structure simulations. They were fabricated by electron beam lithography and dry etching in a suspended membrane. Theoretical work has been carried out considering also the modes of two valley Hall phononic crystals forming an interface waveguide.
The propagation is studied by launching a surface acoustic wave and measuring its amplitude along the waveguide by laser Doppler vibrometry.
Our preliminary observations indicate minimum losses. This work-in-progress confirms the role of critical dimension variability among others.
We discuss the significance of this finding in this frequency regime as a useful approach to transmit information at chip level and hypothesize about improvements as well as integration approaches.