Affiliation
University of Hamburg
Title
Acoustically Induced Pseudomagnetic Fields and Synthetic Hall Voltages in Graphene
Abstract
Strain is an extremely versatile experimental parameter to scrutinize 2D carrier systems. The interaction between a 2DES and a surface acoustic wave (SAW), i.e., an elastic strain wave that propagates along the surface of a material with acoustic velocities, can shed light on correlation physics through measurements of the wave attenution and/or changes in the 2DES conductivity induced by momentum transfer [1]. When SAWs are propagating through graphene, novel effects are expected to emerge [2]. The departure from graphene's flatness by a propagating SAW can lead to the emergence of artificial gauge fields that act on the motion of the Dirac fermions through an associated pseudomagnetic field. In this presentation, we demonstrate the tunability of SAW-induced pseudomagnetic fields using large planar CVD graphene sheets that conform to the deformation of a piezoelectric layer by a SAW. The acoustic wave induces a longitudinal and a synthetic Hall/transverse voltage in the absence of external magnetic fields [3]. The superposition of the synthetic Hall potential and a conventional Hall voltage can annihilate the sample's transverse potential at large external magnetic fields. We show that the magnitude of the transverse voltage is consistent with artificial gauge fields induced by the travelling SAW.
[1] Wixforth et al. Phys. Rev. Lett. 56, 2104 (1986); R. L. Willett et al. in Springer Series in Solid-State Sciences 101, 262 (1992); R. L. Willett et al. Surface Science 305, 76 (1994); R. L. Willett et al. Phys. Rev. Lett. 88, 066801 (2002); M.E. Msall et al. New J. Phys. 17 043042 (2015); "The 2019 surface acoustic waves roadmap", Phys. D: Appl. Phys. 52, 353001 (2019)
[2] A Hernandez-Minguez et al. J. Phys. D: Appl. Phys. 51, 383001 (2018) and references therein
[3] P. Zhao et al. Appl. Phys. Lett. 116, 103102 (2020); P. Zhao et al. Phys. Rev. Lett. 128, 256601 (2022)