| Autor: |
Davidovikj D; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands., Slim JJ; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands., Cartamil-Bueno SJ; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands., van der Zant HS; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands., Steeneken PG; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands., Venstra WJ; Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ, Delft, The Netherlands.; Quantified Air, Lorentzweg 1, 2628 CJ, Delft, The Netherlands. |
| Abstrakt: |
Membranes of suspended two-dimensional materials show a large variability in mechanical properties, in part due to static and dynamic wrinkles. As a consequence, experiments typically show a multitude of nanomechanical resonance peaks, which make an unambiguous identification of the vibrational modes difficult. Here, we probe the motion of graphene nanodrum resonators with spatial resolution using a phase-sensitive interferometer. By simultaneously visualizing the local phase and amplitude of the driven motion, we show that unexplained spectral features represent split degenerate modes. When taking these into account, the resonance frequencies up to the eighth vibrational mode agree with theory. The corresponding displacement profiles, however, are remarkably different from theory, as small imperfections increasingly deform the nodal lines for the higher modes. The Brownian motion, which is used to calibrate the local displacement, exhibits a similar mode pattern. The experiments clarify the complicated dynamic behavior of suspended two-dimensional materials, which is crucial for reproducible fabrication and applications. |
