[en] Alumina template-synthesized nanostructure materials have unique properties which are very attractive and have been under intensive research in recent years. We describe the latest developments in the preparation of one-dimensional magnetic nanowire arrays by electrodeposition. Many kinds of array structures, such as elemental, alloy, multilayer and superlattice nanowires, are reviewed. Future research directions of super-high density magnetic recording and potential applications of the giant magnetic resistance of magnetic nanowires are also discussed. (authors)

No abstract available

[en] The acoustoelectric current in graphene nanoribbons, with widths ranging between 350 nm and 600 nm, has been investigated as a function of illumination. For all nanoribbon widths, the acoustoelectric current was observed to decrease on illumination, in contrast to the increase in acoustoelectric current measured in unpatterned graphene sheet devices. This is thought to be due to the higher initial conductivities of the nanoribbons compared to unpatterned devices. (paper)

[en] Highlights: • GO-SiO₂ rGO-SiO₂ composites were prepared via chemical-thermal method. • HA-SiO₂ and tHA-SiO₂ composites were obtained by wet chemical techniques. • The morpho-structural characteristics of composites were evaluated and compared. • The rGO-SiO₂ and tHA-SiO₂ showed the highest antibacterial effect on E. Coli and S. Aureus.

[en] Several works were used metal as background for generating high absorbance due to destructive interference from the superposition of multiple reflections on metamaterial absorber. In this work, we purpose tailoring multiple reflection by using graphene as background for tunable terahertz metamaterial absorber. Graphene’s properties can be adjusted by an applied voltage. The Fermi energy of graphene was adjusted from 0.2 meV till 1 meV in this work. There is around 0.02%–0.14% error between numerical and analytical calculation of absorbance result due to analytical calculation error process. The adjusting graphene’s properties could tailor the superposition of multiple reflections $\left({\stackrel{~<!--\; ~\; -->}{r}}_m\right)$ on metamaterial unit cell-graphene layer. (paper)

[en] Graphene is as an essential material for light modulation owing to controlling broadband absorption and plasmon excitation. Here, we propose a mid-infrared enhanced plasmonic modulator that integrates double-layer graphene in a reflective structure. It is demonstrated that double-layer graphene can support plasmonic resonances with higher oscillator intensity than single-layer in this modulator. The proposed modulator exhibits a modulation depth up to 21 dB and 3 dB bandwidth of 47.4 GHz over a wide range of wavelength (3.17 µm to 4.4 µm). Moreover, the maximum insertion loss of it is barely about 0.27 dB and the minimum of that is about 0.1 dB. This graphene-based modulator, with combined advantages of high modulation depth, low insertion loss and ultrafast modulation speed, holds potential in efficient manipulating MIR lights in free space communication. (paper)

[en] We show that the optical excitation of multi-valley systems leads to valley currents which depend on the light polarization. The net electric current, determined by the vector sum of single-valley contributions, vanishes for some peculiar distributions of carriers in the valley and momentum spaces forming a pure valley current. We report on the study of this phenomenon, both experimental and theoretical, for graphene and 2D electron channels on the silicon surface

[en] Random fluctuations of the shot-noise power in disordered graphene nanoribbons are studied. In particular, we calculate the distribution of the shot noise of nanoribbons with zigzag and armchair edge terminations. We show that the shot noise statistics is different for each type of these two graphene structures, which is a consequence of the presence of different electron localizations: while in zigzag nanoribbons electronic edge states are Anderson localized, in armchair nanoribbons edge states are absent, but electrons are anomalously localized. Our analytical results are verified by tight binding numerical simulations with random hopping elements, i.e., off diagonal disorder, which preserves the symmetry of the graphene sublattices.

[en] Highlights: • The transition between a fused-ring structure toward its single-ring counterpart is studied. • The change occurs at certain structure instead of a gradual transition. • The fused counterparts can be treated as a modification in the aromatic path of a single ring aromatic motif. • Useful approach to evaluate the formation of defects or larger-rings in graphene motifs. The fused-to-single-ring transition is studied through a 10πe series given the series from naphthalene to [10]annulene. Our results suggest that change occurs at certain structure instead of a gradual transition. In the transition point, given by bicyclo[7.1.0]decapentaene, similar magnetic behavior in comparison to the single ring counterpart is found. The systems can be considered to behave as a whole single aromatic structure where the fused counterparts can be treated as a modification in the aromatic path of a single ring aromatic motif, which can viewed as a useful approach to evaluate the formation of defects or larger-rings in graphene motifs.

[en] A Hall resistivity formula for the 2DES in graphene is derived from the zero-mass Dirac field model adopting the electron reservoir hypothesis. The formula reproduces perfectly the experimental resistivity data [K.S. Novoselov, et al., Nature 438 (2005) 201]. This perfect agreement cannot be achieved by any other existing models. The electron reservoir is shown to be the 2DES itself. -- Highlights: ► Quantum Hall resistivity formula is derived from the zero-mass Dirac model. ► The formula agrees with the graphene experiment perfectly. ► No existing theories can explain the experiment quantitatively. ► The electron reservoir hypothesis is adopted. ► Mechanism of the electron reservoir is clarified for the first time.