Piezoelectric coupling of surface acoustic waves in two-dimensional heterostructures

초록

In electronic devices based on two-dimensional (2D) materials that utilize surface acoustic waves (SAWs), it is crucial to understand the interaction between 2D materials and piezoelectric substrates. Here, we systematically investigate this interaction through numerical modeling of a van der Waals heterostructure comprising graphene encapsulated by hexagonal boron nitride. Our simulations focus on the role of dielectric thickness and gate-layer conductivity in determining the strength and efficiency of SAW-driven electric potentials. Results reveal that the amplitude of the SAW-induced electric potential in graphene decline exponentially with increasing dielectric thickness. Conducting-gate layers introduce pronounced screening effects, with back-gate significantly reducing the amplitude of the SAW-induced electric potential compared to top-gate due to their direct screening of electric fields. Additionally, conducting graphene layer itself leads to a self-intrinsic screening that reduces the amplitude of the SAW-induced electric potential. Our study provides quantitative insights into optimizing device configurations and conductivity parameters, offering clear strategies for improving the sensitivity and effectiveness of SAW-based 2D electronic devices for quantum and sensing applications.