SearcharxivSearch

arXiv subjects

A. K. Twum

Publications and source records attributed to A. K. Twum.

2 recordsLinked to original sources

Acoustoelectric Effect in degenerate Carbon Nanotube

Acoustoelectric Effect $AE$ in degenerate Carbon Nanotube ($CNT$) was theoretically studied for hypersound in the regime $ql >> 1$. The dependence of acoustoelectric current $j^{ac}$ on the acoustic wave number $\vec{q}$ and frequency $ω_q$ at $T = 10K$ and scattering angle ($θ> 0$) was evaluated at various harmonics $n =\pm 1, 2, ...$ (where $n$ is an integer). In the first harmonics ($n = \pm 1$), the non-linear dependence of $j^{ac}$ on $ω_q$ and $\vec{q}$ were obtained. For $n = \pm 2$, the numerically evaluated $j^{ac}$ qualitatively agreed with an experimentally obtained result.

cond-mat.mes-hall

Negative Differential Conductivity in Carbon Nanotubes in the Presence of an External Electric Field

We study theoretically the electron transport properties in carbon nanotubes under the influence of an external electric field E(t) using Boltzmann's equation. The current-density equation is derived. Negative differential conductivity is predicted when ωτ<<1 (quasi-static case). We observed this in the neighbourhood where the constant electric field E_o is equal to the amplitude of the AC electric field E_1 and the peak decreases with increasing E_1. This phenomenon can also be used for the generation of terahertz radiation without electric current instability.

cond-mat.mes-hall