Dynamic Carrier Modulation via Nonlinear Acoustoelectric Transport in van der Waals Heterostructures.

McSorley, Timothy J; Simha, Kaustubh; Corcoran, James E; Catanzaro, Izzie J; Zhang, Haochong; Yin, Meitong; Lu, Tzu-Ming; Thuillier, Davis et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Dynamically manipulating carriers in van der Waals heterostructures could enable solid-state quantum simulators with tunable lattice parameters. A key requirement is the formation of deep potential wells to reliably trap excitations. Here, we report the observation of nonlinear acoustoelectric transport and dynamic carrier modulation in boron nitride-encapsulated graphene devices coupled to intense surface acoustic waves (SAWs) on LiNbO<sub>3</sub> substrates. SAWs generate strong acoustoelectric current densities (<i>J</i><sub><i>AE</i></sub>), transitioning from linear to nonlinear regimes with increasing SAW intensity. In the nonlinear regime, periodic carrier (electrons, holes, or their mixtures) stripes emerge. Using counter-propagating SAWs, we create standing SAWs (SSAWs) to dynamically manipulate charge distributions without static gates. The saturation of <i>J</i><sub><i>AE</i></sub>, attenuation transitions, and tunable resistance peaks confirms strong carrier localization. These results establish SAWs as a powerful tool for controlling carrier dynamics in two-dimensional (2D) materials, paving the way for the development of time-dependent quantum systems and acoustic lattices for quantum simulation.