Towards tunable graphene phononic crystals

Phononic crystals (PnCs) are artificially patterned media exhibiting bands of allowed and forbidden zones for phonons-in analogy to the electronic band structure of crystalline solids arising from the periodic arrangement of atoms. Many emerging applications of PnCs from solid-state simulators to quantum memories could benefit from the on-demand tunability of the phononic band structure. Here, we demonstrate the fabrication of suspended graphene PnCs in which the phononic band structure is controlled by mechanical tension applied electrostatically. We show signatures of a mechanically tunable phononic band gap. The experimental data supported by simulation suggests a phononic band gap at 28-33 MHz in equilibrium, which upshifts by 9 MHz under a mechanical tension of 3.1 N m(-1). This is an essential step towards tunable phononics paving the way for more experiments on phononic systems based on 2D materials.

Automated summary

Phononic crystals (PnCs) are artificially patterned media that exhibit phononic band structure similar to the electronic band structure of crystalline solids. In this study, we demonstrate the fabrication of suspended graphene PnCs, where the phononic band structure can be controlled by electrostatically applied mechanical tension. Experimental and simulation results show a mechanically tunable phononic band gap of 28-33 MHz, which can be shifted by 9 MHz under a mechanical tension of 3.1 N m(-1). This work is an important step towards the development of tunable phononics based on 2D materials.