Quantum Transport in Graphene Using Surface Acoustic Wave Resonators

TL;DR

This paper demonstrates the use of surface acoustic wave resonators on LiNbO3 substrates to perform contactless quantum transport measurements in high-mobility graphene heterostructures, opening new avenues for studying vdW materials.

Contribution

It introduces a novel application of SAW resonant cavities on LiNbO3 for accessing the quantum Hall regime in graphene heterostructures.

Findings

SAW resonant cavities can probe quantum Hall effects in graphene.

The technique is contactless and suitable for van der Waals heterostructures.

Established a platform for future quantum transport studies in 2D materials.

Abstract

Surface acoustic waves (SAWs) provide a contactless method for measuring the wavevector-dependent conductivity. This technique has been used to discover emergent length scales in the fractional quantum Hall regime of traditional, semiconductor-based heterostructures. SAWs would appear to be an ideal match for van der Waals (vdW) heterostructures, but the right combination of substrate and experimental geometry to allow access to the quantum transport regime has not yet been found. We demonstrate that SAW resonant cavities fabricated on LiNbO$_3$ substrates can be used to access the quantum Hall regime of high-mobility, hexagonal boron nitride (hBN) encapsulated graphene heterostructures. Our work establishes SAW resonant cavities as a viable platform for performing contactless conductivity measurements in the quantum transport regime of vdW materials.