Volume 11 Issue 11, November 2012

An algorithm that allows the atomic-scale reconstruction of the three-dimensional structure of nanoparticles from only four individual images provides an important step towards fast, in situ electron tomography.

Interstitials and other localized defects in flat crystals are stable, yet interstitials in curved crystals can instead fractionalize. This observation should lead to a more general understanding of how to tailor defects in both classical and quantum crystalline systems.

Toxic metal cations in environmental samples can be detected with ultrahigh sensitivity through measurements of the tunnelling current across crosslinked films of nanoparticles decorated with striped monolayers of organic ligands.

When cooled in water from high temperature, superhydrophobic surfaces stabilize the vapour layer on them, thus avoiding the typical vapour explosions associated with the nucleation of bubbles.

Metamaterials are man-made structures that allow optical properties to be shaped on length scales far smaller than the wavelength of light. Although metamaterials were initially considered mainly for static applications, this Review summarizes efforts towards an active functionality that enables a much broader range of photonic device applications.

Whether a liquid forms a crystal or a glass on solidification depends on many factors. The finding now that a disordered structure is favoured in B₂O₃ because the system cannot choose between several crystalline polymorphs of similar energy highlights a link between glass formation and crystallization.

The atomic structure of nanoparticles considerably influences their properties. A new methodology that is now able to measure the full three-dimensional atomic structure of free-standing nanoparticles will therefore provide a much better connection between their structure and properties.

The properties of graphene have been widely studied for applications in electronics. Expanding its use in photonics as well, it is now demonstrated that the propagation of terahertz waves can be electronically switched by such a single atomic layer of carbon.

Nickel-rich layered lithium transition metal oxides have been investigated as high-energy cathode materials for rechargeable lithium batteries because of their high specific capacity and relatively low cost. Such an oxide with high capacity (215 mA h g^-1), where the nickel concentration decreases linearly whereas the manganese concentration increases linearly from the centre to the outer layer of each particle, is now proposed.

Understanding the consequences of the interplay of defects and local curvature in crystals is far from complete despite the considerable influence that a defect has on the crystal’s local properties. It is now found that interstitials inserted in curved crystals at oil/glycerol interfaces can fractionate into two dislocations, which glide through the lattice in opposite directions until they get absorbed into existing dislocations, scars or pleats.

Phase-change materials show an unusual metal–insulator transition that is induced by disorder in the crystalline state. Numerical computations now show how the transition to the metallic state proceeds from the dissolution of electronic states situated at vacancy clusters to the formation of ordered vacancy layers.

The origin of the magnetism in manganese-doped gallium arsenide has been the subject of much debate. Now, hard X-ray angle-resolved photoemission has been used to probe the electronic structure of this material and clarify the mechanism through which the magnetism arises.

Controlling surface structure at the atomic scale is paramount to developing effective catalysts. The surface structure of MoS₂ is now engineered to preferentially expose edge sites by successfully synthesizing contiguous large-area thin films of a highly ordered double-gyroid MoS₂ bicontinuous network with nanoscale pores.

A major obstacle to fully understanding the catalytic mechanisms of oxygen reduction reactions and to designing more efficient catalysts is the lack of detailed information about the active site structure. Molecular local chemisorption sites and the long-range supramolecular arrangement of metallophthalocyanine molecules on a metal surface can now be controlled by the fine tuning of the overlayer coverage.

Solid-state sensors for the detection of heavy-metal cations require for the most part sophisticated chemistry and equipment. It is now shown that toxic cations in environmental samples can be detected with ultrahigh sensitivity and over a broad range of cation concentrations by measuring the tunnelling current across films of nanoparticles decorated with striped monolayers of organic ligands.

Three-dimensional bioactive scaffolds can support tissue growth for studies in cellular biophysics and regenerative medicine. Such scaffolds have now been integrated with semiconductor nanowires to probe their porous interior, allowing for real-time monitoring of signals such as the response of neural and cardiac tissue models to drugs.