Volume 7 Issue 6, June 2008

Several approaches are capable of beating the classical 'diffraction limit'. In the optical domain, not only are superlenses a promising choice: concepts such as super-oscillations could provide feasible alternatives.

The room-temperature manipulation of magnetization by an electric field using the multiferroic BiFeO₃ represents an essential step towards the magnetoelectric control of spintronics devices.

With the extension of a popular computational method to its tensorial analogue, structural configurations that optimize anisotropic physical quantities can now be predicted.

The spectral complexity shown by conjugated polymers has been explained by interactions between chromophores in tangled chains, but experiments on model oligomers reveal that it may arise from the chromophores themselves.

In an identification parade of chemical reactions using a single-electrode system, the charges generated by the mechanical rubbing of insulators are shown to be electrons rather than ions.

Meeting their biological counterparts halfway, artificial molecular machines embedded in liquid crystals, crystalline solids and mesoporous materials are poised to meet the demands of the next generation of functional materials.

Physicist, karate master, and pioneer in optical properties of nanostructures

The resolution of conventional optical instruments is limited to length scales of roughly the wavelength of the light used. Nanoscale superlenses offer a solution for achieving much higher resolutions that may find appllications in many imaging areas.

Cluster expansion has been a particularly successful computational method that has allowed the identification of the relationship between lattice configurations and scalar properties in crystals. A tensorial version of the method that will enable prediction of tensor-valued properties is now introduced. It is validated by predicting anisotropic properties relevant to semiconductor optoelectronic devices.

Composites with added carbon nanotubes are known for their improved mechanical strength. Laminates of thin films of aluminium and carbon nanotubes are now used for the fabrication of micromechanical resonators with significantly enhanced mechanical properties.

Diluted magnetic semiconductor devices where magnetism can be controlled by an electric field are of significant interest for applications, as they combine the appealing properties of multiferroics with existing semiconductor technology. By using a ferroelectric polymer as the gate of a transistor device, non-volatile electric control over the magnetism of (Ga,Mn)As has now been achieved.

X-ray diffraction computed tomography can provide high-resolution phase mapping of nanocrystalline and powdered crystalline materials. Moreover, a reverse analysis offers the possibility to extract, a posteriori, the scattering/diffraction pattern from a selected area of the tomography image.

The electric polarization of dipoles on the surface of a ferroelectric material can influence the energetics of materials adsorption. The demonstration of this effect on the physisorption kinetics of gases such as carbon dioxide may be used to control adsorption and surface chemistry on the nanoscale.

Multiferroic materials are of interest because they allow control of their magnetic properties through electric fields. However, room-temperature magnetoelectrics often show antiferromagnetic order, reducing the effects of such coupling. A novel approach demonstrates switchable electric field control over a local magnetic field through the indirect route of exchange bias.

Understanding how excited states behave at heterojunctions between polymers in blends is fundamental to designing better organic solar cells and light-emitting diodes. A quantum-mechanical molecular-scale model of how excitations behave at heterojunctions has been developed, showing an unexpectedly wide but specific range of excitonic states.

Organic holographic materials are pursued as versatile and cheap data-storage materials. However, previously such materials either needed the application of an external electric field or had mostly poor efficiencies. Now, a novel recording process based on a photoisomerization process demonstrates significantly improved writing properties of holograms.

Fast-ion conductors are needed to reduce the operating temperature of solid-oxide fuel cells. The identification of the conduction mechanism in electrolytes where conduction is based on mobile oxygen interstitials rather than the usual anion vacancies offers a generic design principle for novel solid electrolytes.

The nature of electrostatic charges produced at the surface of insulators by rubbing is the subject of a long-standing discussion. The charges created on polytetrafluoroethylene by rubbing with polymethylmethacrylate are identified here to be electrons rather than ions.

Surface plasmons are collective motions of electrons at the surface of a metal that can strongly amplify local electromagnetic fields. This special issue looks at the exciting possibilities in sub-wavelength imaging and biosensing enabled by surface plasmons.