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.
Long linear carbon chains encapsulated inside carbon nanotubes are a very close realization of carbyne, the truly one-dimensional allotrope of carbon. Here we study individual pairs of double-walled carbon nanotubes and encapsulated linear carbon chains by tip-enhanced Raman scattering. We observe that the radial breathing mode of the inner nanotube correlates with the frequency of the carbon chain's Raman mode, revealing that the nanotube chirality determines the vibronic and electronic properties of the encapsulated carbon chain. We provide the missing link that connects the properties of th…
Local Semiconducting Transition in Armchair Carbon Nanotubes: The Effect of Periodic Bi-site Perturbation on Electronic and Transport Properties of Carbon Nanotubes
We present a two-step procedure to probe hotspots of plasmon-enhanced Raman scattering with carbon nanotubes. Dielectrophoretic deposition places a small carbon nanotube bundle on top of plasmonic Au nanodimer. After 'pre-characterising' both the nanotubes and dimer structure, we subsequently use the tip of an AFM to push the bundle into the plasmonic hotspot located in the 25nm wide dimer gap, characterize its location inside the gap, and observe the onset of plasmon-enhanced Raman scattering. Evidence for the activation of the carbon nanotube's double-resonant D-mode by the near-field of the…
Photoluminescent carbon nanotubes are expected to become versatile room-temperature single-photon sources that have applications in quantum information processing. Quantum emission from carbon nanotubes is often induced by localization of excitons or exciton-exciton annihilation. Here, we modify the local energy landscape of excitons by decorating nanoscale pentacene particles onto air-suspended single-walled carbon nanotubes. Directional exciton diffusion from the undecorated region to the decorated site is demonstrated, suggesting exciton trapping induced by local dielectric screening from p…
We demonstrate theoretically that an off-resonant circularly polarized electromagnetic field can induce a persistent current in carbon nanotubes, which corresponds to electron rotation about the nanotube axis. As a consequence, the nanotubes acquire magnetic moment along the axis, which depends on their crystal structure and can be detected in state-of-the-art measurements. This effect and related phenomena are analyzed within the developed Floquet theory describing the electronic properties of the nanotubes irradiated by the field.
Single wall carbon nanotubes cooled to cryogenic temperatures are outstanding electronic as well as nano-electromechanical model systems. To probe a largely unperturbed system, we measure a suspended carbon-nanotube device where the nanotube is grown in the last fabrication step, thus avoiding damage and residues from subsequent processing. In this ultra-clean device, we observe the transport spectrum and its interaction with nano-electromechanics over a wide gate voltage range and thereby over a wide range of coupling parameters between the quantum dot and the contact electrodes.
Zitterbewegung (ZB, trembling motion) of electrons in semiconductor carbon nanotubes is described taking into account dephasing processes. The density matrix formalism is used for the theory. Differences between decay of ZB oscillations due to electron localization and that due to dephasing are discussed.
The efficiencies of photonic devices are primarily governed by radiative quantum efficiency, which is a property given by the light emitting material. Quantitative characterization for carbon nanotubes, however, has been difficult despite being a prominent material for nanoscale photonics. Here we determine the radiative quantum efficiency of bright excitons in carbon nanotubes by modifying the exciton dynamics through cavity quantum electrodynamical effects. Silicon photonic crystal nanobeam cavities are used to induce the Purcell effect on individual carbon nanotubes. Spectral and temporal b…
The measured electric resistance of carbon nanotubes wrapped with DNA molecules depends strongly on the spin of the injected electrons. Motivated by these experiments, we study the effect of helix-shaped potentials on the electronic spectrum of carbon nanotubes. We find that in combination with the curvature-induced spin-orbit coupling inherent to nanotubes, such a perturbation opens helicity-dependent gaps. Within these partial gaps, left-moving electrons carry a fixed spin-projection that is reversed for right-moving electrons, and the probability of electrons to transfer through the nanotub…
Phonon Dispersion in Chiral Single Wall Carbon Nanotubes
从$6\times 6$动力学矩阵出发，计算了手性单壁碳纳米管的声子色散。本文是G. D. Mahan和Gun Sang Jeon在扶手椅和锯齿形纳米管上的工作。[see P. R. B、{ \bf 70}，075405（2004）]。我们采用弹簧-质量模型，并采用\cite{M2}建议的适当声子势。我们可以计算任意手性的单壁碳纳米管在$Γ$点附近的色散。结果与Mahan et. al的扶手椅型和锯齿型单壁碳纳米管的结果。
