Interactions between surface acoustic waves and charge carriers in quantum materials
Interactions between surface acoustic waves and charge carriers in quantum materials
Surface acoustic waves (SAWs) on piezoelectric insulators can generate dynamic periodic potentials inside one-dimensional and two-dimensional materials. These periodic potentials have been utilized or proposed for various applications, which I will review in this presentation. One such application is acoustoelectric charge pumping, which I have investigated in my experiments on specially fabricated graphene devices that have very low electrostatic disorder. By employing a graphite top gate on boron-nitride-encapsulated graphene, I adjust the graphene carrier concentration over a broad range, enabling us to examine the acoustoelectric signal in both mixed-carrier and single-carrier regimes. I will discuss the benefits of hBN-encapsulated graphene for charge pumping applications and introduce a model that describes the acoustoelectric signal across all carrier concentrations, including at the charge neutrality point. This quantitative model will support future SAW-enabled explorations of phenomena in low-dimensional materials and guide the design of novel SAW sensors.