Amplification of Hypersound in Graphene with degenerate energy dispersion

Abstract

Hypersound amplification/absorption of acoustic phonons in Graphene with degenerate energy dispersion $\epsilon (p)$ near the Fermi level was theoretically studied. For $k_{\beta }T<<1$ and $ql>>1$, the dependence of the absorption coefficient $\Gamma /{\Gamma }_0$ on $\frac{V_D}{V_s}$ was studied where the results satisfied the Cerenkov effect. That is when $\frac{V_D}{V_s}>1$, an amplification was obtained but for $\frac{V_D}{V_s}<1$, an absorption was obtained which could lead to Acoustoelectric Effect (AE) in Graphene. A linear dependence of the $\Gamma /{\Gamma }_0$ on ${\omega }_q$ was observed where the result obtianed qualitatively agreed with an experimentally observed acoustoelectric current in Graphene via the Weinrich relation. It is interesting to note from this study that, frequencies above $10THz$ can be attained for $V_D=1.1m{s}^{-1}$. This study permit the use of Graphene as hypersound phonon laser (SASER).

13 pages, 6 figures

References in corpus (2)

• The electronic properties of graphene
• Surface Acoustic Wave Amplification by DC-Voltage Supplied to Graphene Film

Cited by in corpus (2)

• Amplification of Acoustic Waves in Graphene Nanoribbon in the Presence of External Electric and Magnetic Field
• Acoustoelectric Effect in Graphene with degenerate Energy dispersion