Acoustoelectric current in graphene nanoribbon due to Landau damping

K A Dompreh,N G Mensah,A Twum,D Sakyi-Arthur,M Amekpewu,S Y Mensah,K W Adu

doi:10.1038/s41598-021-95896-6

Abstract

We perform self-consistent analysis of the Boltzmann transport equation for momentum and energy in the hypersound regime i.e., ql gg 1 (q is the acoustic wavenumber and l is the mean free path). We investigate the Landau damping of acoustic phonons (LDOAP) in graphene nanoribbons, which leads to acoustoelectric current generation. Under a non-quantized field with drift velocity, we observed an acoustic phonon energy quantization that depends on the energy gap, the width, and the sub-index of the material. An effect similar to Cerenkov emission was observed, where the electron absorbed the confined acoustic phonon energy, causing the generation of acoustoelectric current in the graphene nanoribbon. A qualitative analysis of the dependence of the absorption coefficient and the acoustoelectric current on the phonon frequency is in agreement with experimental reports. We observed a shift in the peaks when the energy gap and the drift velocity were varied. Most importantly, a transparency window appears when the absorption coefficient is zero, making graphene nanoribbons a potential candidate for use as an acoustic wave filter with applications in tunable gate-controlled quantum information devices and phonon spectrometers.

Highlights

We perform self-consistent analysis of the Boltzmann transport equation for momentum and energy in the hypersound regime i.e., ql ≫ 1 ( q is the acoustic wavenumber and l is the mean free path)
Landau damping of acoustic phonons (LDOAP) occurs in the hypersound regime during electron–phonon interactions[4, 5]
This phenomenon leads to an absorption or amplification of acoustic p honons[9], as observed in the acoustoelectric effect (AE)[10], acoustomagnetoelectric effect (AME)[11,12,13], acoustothermal effect (ATE)[14] and acoustomagnetothermal effect (ATME)[15, 16]

Summary

Introduction

We perform self-consistent analysis of the Boltzmann transport equation for momentum and energy in the hypersound regime i.e., ql ≫ 1 ( q is the acoustic wavenumber and l is the mean free path). Zhang et al.[44] obtained a strong absorption when the carrier density and the field were increased as a result of electrons colliding with the acoustic phonons under a drift electric field. Considering acoustic phonons as quantized sound waves of frequency ( ωq ), the conducting electrons can absorb the sound energy.

Results

Conclusion