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We have theoretically investigated electronic, magnetic, and thermal properties of a graphene-diamond hybrid structure consisting of a graphene nanoribbon with zigzag edges connected to diamond surfaces. From the first-principles calculation, we found that the hybrid structure is stable and that the ferro-magnetically ordered edge state appears around the graphene-diamond. On the other hand, from the non-equilibrium molecular dynamics simulations, we found that the thermal conductance at the interface between the graphene and diamond is 7.01 ± 0.05 GWm-2K-1 at the room temperature, which is much larger than that for covalently bonded interface between carbon nanotube and silicon. Thus, we propose that the hybrid structure is a potential candidate for spin-polarized conducting wires with thermally efficient heat sinks. [ABSTRACT FROM AUTHOR]

To realize single-walled carbon nanotube (SWCNT) chiral selective growth, elucidating the mechanism of SWCNT chirality (n , m) selectivity is important. For this purpose, an accurate evaluation method for evaluating the chirality distribution of grown SWCNTs without post-growth processing or liquid-dispersion of SWCNTs is indispensable. Here, we used photoluminescence spectroscopy to directly measure the chirality distributions of individual semiconducting SWCNTs suspended on a pillar-patterned substrate. The number of chirality-assigned SWCNTs was up to 332 and 17 chirality types with the chiral angles ranging from 0 ° to 28.05 ° were detected. The growth yield of SWCNTs was confirmed to primarily depends on the chiral angle in accordance with the screw dislocation model. Furthermore, when higher-yield chiralities are selected, the chiral angle distribution with a peak corresponding to near-armchair SWCNTs is well fitted with a model that incorporates the thermodynamic effect at the SWCNT-catalyst interface into the kink growth-based kinetic model. Our quantitative and statistical data provide new insights into SWCNT growth mechanism as well as experimental confirmation of theoretical predictions. [ABSTRACT FROM AUTHOR]

We present a method for controlling the electron- and phononderived thermal conductances in carbon nanotubes with vacancy defects involving numerical analysis based on the nonequilibrium electron/phonon Green's function method. The electron-derived thermal conductance can be controlled by tuning the external gate voltage because the resonant backscattering level (dangling σ-bond states around vacancies) can be shifted by the gate voltage. In contrast, thermal annealing is effective in increasing the phonon-derived thermal conductance because the quasi-bound phonon state localized around a vacancy disappears due to the annealing-induced vacancy rearrangement. [ABSTRACT FROM AUTHOR]

The universal behavior of low-temperature thermal conductance in single-walled carbon nanotubes is revealed within the framework of the Landauer theory of heat transport. The phonon-derived thermal conductance is quantized as a universal value of π2kB2T/3h in the low-temperature limit, T→0, independent of radius or chirality. The temperature dependence follows a single curve given in terms of temperature scaled by the energy gap of the lowest optical mode. In contrast, the electronic contribution to thermal conductance at low temperature is found to be strongly dependent on the tube geometry responsible for the electronic states. [Copyright &y& Elsevier]

Hydrophilicity or hydrophobicity is a macroscopic property of the surface, and its atomic scale understanding has not been established. We have studied adsorption of water molecules on the "hydrophobic" carbon nanotube surface at room temperature in water vapor. Based on optical measurements of individual single-walled carbon nanotubes suspended between micropillars in water vapor together with molecular dynamics simulations, we found that water molecules form a stable adsorption layer of 1-2 ML thickness on the nanotube surface and they show rapid adsorption and desorption transition at a critical pressure. This adsorption layer is created by lateral hydrogen bonding of water molecules confined in the weak van der Waals potential of the surface. In spite of hydrophobic hydration, carbon nanotubes exhibit hydrophobicity macroscopically. [ABSTRACT FROM AUTHOR]