Tunable Graphene Phononic Crystal

In the field of phononics, periodic patterning controls vibrations and thereby the flow of heat and sound in matter. Bandgaps arising in such phononic crystals PnCs realize low dissipation vibrational modes and enable applications toward mechanical qubits, efficient waveguides, and state of the art sensing. Here, we combine phononics and two dimensional materials and explore tuning of PnCs via applied mechanical pressure. To this end, we fabricate the thinnest possible PnC from monolayer graphene and simulate its vibrational properties. We find a bandgap in the megahertz regime within which we localize a defect mode with a small effective mass of 0.72 ag 0.002 mphysical. We exploit graphene s flexibility and simulate mechanical tuning of a finite size PnC. Under electrostatic pressure up to 30 kPa, we observe an upshift in frequency of the entire phononic system by amp; 8764;350 . At the same time, the defect mode stays within the bandgap and remains localized, suggesting a high quality, dynamically tunable mechanical syste