Towards quantum pumps: Charge pumping in boron-nitride-encapsulated low-dimensional conductors using surface acoustic waves

Interfacing surface acoustic waves with nanomaterials is a promising approach for sensor technology [1] and for probing previously inaccessible phenomena in low-dimensional electronic systems [2,3]. However, achieving the full potential of these systems requires pristine materials with low electronic disorder.

We present results on acoustoelectric charge pumping in boron nitride-encapsulated graphene on lithium niobate. Our device uses a solid-state graphene gate, which avoids the drawbacks of ionic liquid gates, such as acoustic damping, while still allowing for strong modulation of charge carrier concentration. We demonstrate that our device produces higher-magnitude and lower-noise acoustoelectric current than previously reported devices, and we discuss plans for using this platform to achieve topologically protected charge pumping.

[1] S. Yang, C. Jiang, and S-huai Wei, “Gas Sensing in 2D Materials,” Appl. Phys. Rev. 4, 021304 (2017)

[2] Y. Fang, Y. Xu, K. Kang, B. Davaji, et al., “Quantum Oscillations in Graphene Using Surface Acoustic Wave Resonators,” Phys. Rev. Lett. 130, 246201 (2023).

[3] D. S. Novikov, “Devil’s Staircase of Incompressible Electron States in a Nanotube,” Phys. Rev. Lett. 95, 1 (2005).