Influence of external temperature gradient on acoustoelectric current in graphene

TL;DR

This paper theoretically investigates how an external temperature gradient influences the acoustoelectric current in free-standing graphene, revealing potential for thermal amplification and logic applications.

Contribution

It provides a detailed theoretical analysis of the effect of temperature gradients on acoustoelectric current in graphene, including calculations of thermal fields and current magnitudes.

Findings

Acoustoelectric current in graphene is comparable to semiconductors under certain temperature gradients.

Negative Difference Conductivity observed, indicating potential for thermal amplification.

Graphene shows promise for developing thermal amplifiers and logic gates.

Abstract

Recent analyses of thermoelectric amplification of acoustic phonons in Free-Standing Graphene (FSG) $\Gamma_q^{grap}$ have prompted the theoretical study of the influence of external temperature gradient ($\nabla T$) on the acoustoelectric current $j_T^{(grap)}$ in FSG. Here, we calculated thermal field on open circuit ($j_T^{(grap)} = 0$) to be $(\nabla T)^g = 746.8Km^{-1}$. We then calculated acoustoelectric current ($j_T^{(grap)}$)to be $1.1mA\mu m^{-2}$ for $\nabla T = 750.0 Km^{-1}$, which is comparable to that obtained in semiconductors ($1.0mA\mu m^{-2}$), the thermal-voltage $(V_T)_0^g$ to be $6.6\mu V$ and the Seebeck coefficient $S$ as $8.8\mu V/K$. Graphs of the normalized $j_T^{(grap)}/j_0$ versus $\omega_q$, $T$ and $\nabla T/T$ were sketched. For $j_T^{(grap)}$ on $T$ for varying $\omega_q$, Negative Difference Conductivity (NDC) ($| \frac{\partial j}{\partial T}| < 0$) was observed in the material. This indicates graphene is a suitable material for developing thermal amplifiers and logic gates.