Acoustoelectric effect in bilayer graphene due to intrinsic deformation potential and extrinsic piezoelectric phonon couplings

Bilayer graphene (BLG) has been found to exhibit electronic properties that are either altogether unique to it, or if similar to single-layer graphene (SLG) then they differ in character and intensity. In this article, we focus our investigation on the amplification/attenuation and acoustoelectric current phenomena in BLG generated through piezoelectric and deformation potential electron–phonon coupling mechanisms. We conducted a comprehensive exploration of the kinetic equations within the Boltzmann transport framework, examining both analytical and numerical estimation of the acoustoelectric current and amplification coefficient. Notably, we observe a noteworthy change in the generation of acoustoelectric current in BLG that occurs at much lower (KHz) frequencies as compared to SLG, where the current of the same magnitude occurred at the MHz frequency range. Also, the acoustoelectric current in BLG follows a linear relationship with frequency \(({\omega }_{q})\).

Graphical abstract

Schematics of a bilayer graphene sheet placed on a piezoelectric substrate (GaAs) between two IDT devices. A surface acoustic waves (SAW) is generated by a high-frequency signal input to IDT1 formed on a piezoelectric substrate which reaches IDT2 where it is converted back into high frequency signal for detection. When a SAW propagates in graphene, an acoustoelectric current (\({I}_{AEB}\)) flows between two attached electrodes.