Gate-Tunable Quantum Acoustoelectric Transport in Graphene
Yicheng Mou, Haonan Chen, Jiaqi Liu, Qing Lan, Jiayu Wang, Chuanxin Zhang, Chuanxin Zhang, Yuxiang Wang, Jiaming Gu, Tuoyu Zhao, Xue Jiang, Wu Shi, Cheng Zhang, Cheng Zhang
Abstract
Transport probes the motion of quasi-particles in response to external excitations. Apart from the well-known electric and thermoelectric transport, acoustoelectric transport induced by traveling acoustic waves has rarely been explored. Here, by adopting hybrid nanodevices integrated with piezoelectric substrates, we establish a simple design of acoustoelectric transport with gate tunability. We fabricate dual-gated acoustoelectric devices based on hBN-encapsulated graphene on LiNbO 3 . Longitudinal and transverse acoustoelectric voltages are generated by launching a pulsed surface acoustic wave. The gate dependence of zero-field longitudinal acoustoelectric signal presents strikingly similar profiles to that of Hall resistivity, providing a valid approach for extracting carrier density without magnetic field. In magnetic fields, acoustoelectric quantum oscillations appear due to Landau quantization, which are more robust and pronounced than Shubnikov-de Haas oscillations. Our work demonstrates a feasible acoustoelectric setup with gate tunability, which can be extended to the broad scope of various van der Waals materials.