Articles in 2011

Would the publication of anonymous referee reports and editorial decision letters of published papers benefit the scientific debate? Results from a trial seem to suggest this.

Bodies in relative motion, separated by nanometres of vacuum, experience a tiny friction force. Experiments involving a conductor–superconductor transition provide essential information for distinguishing the contribution of electrons from that of lattice vibrations in this non-contact form of friction.

Metallic glasses are strong but can be brittle. The discovery of a metallic glass that also shows a high toughness against fracture is remarkable, and establishes metallic glasses, at least those based on noble metals, as materials with the highest known damage tolerance.

A knot-containing protein is found to fold reversibly at biologically relevant timescales despite not having naturally evolved for this ability.

By combining gene cloning and amplification techniques, a new one-pot, parallel synthesis method for the generation of long, repetitive genes is realized. The method promises to open up the discovery of protein polymer biomaterials.

Single dopants in semiconductors have an atom-like electron-energy spectrum whose discrete character gives them the potential for applications such as quantum information or transistors. This Review describes the marked advances in the past decade towards observing, controllably creating and manipulating single dopants, as well as their application in devices.

Electronic devices based on complex oxides offer the possibility to connect electrical devices with phenomena such as magnetism and superconductivity. However, existing oxide field-effect transistors have drawbacks such as high operation voltage. The demonstration of a metal-base transistor whose geometry makes use of the strong internal electric fields in oxide heterojunctions may now offer a new platform for oxide electronics.

A one-pot, high-throughput method for the recombinant polymerization of monomer DNA sequences is reported. The method enables the rapid synthesis of diverse libraries of artificial repetitive polypeptides, exemplified by the isolation of protease-responsive polymers and a family of polypeptides with reversible thermally responsive behaviour.

Devices that can field-ionize gas molecules at low bias voltages are promising for selective gas-sensing applications and for ion-mobility spectrometry. Field ionization is now observed at very low voltage on semiconducting whiskered silicon nanowires.

The control over phase transitions in complex oxides offers the possibility to control their electronic and structural properties. The discovery of a new route to ultrafast photoswitching of manganites via high-energy ‘hidden’ excited states offers the possibility of phase transitions free from thermal effects.

Transmission electron microscopy (TEM) has reached unprecedented resolution and can provide structural information down to the single atomic level. It is now shown that a properly designed experimental analysis also allows the charge distribution around a single atomic dopant to be monitored, demonstrating the possibility of TEM to provide electronic as well as structural information.

Considerable attention has been given in the past few years to two-dimensional electron gases formed at the interface between two bulk insulators. It is now shown that a similar electronic system can be created on the surface of an oxide insulator simply by exposure to UV light.

Metallic glasses are strong but at the same time are brittle once they yield. A new Pd-based metallic glass now shows significantly enhanced fracture toughness. The unique combination of yield strength and toughness makes this glass comparable to the toughest as well as strongest materials known.

Is friction dominated by electrons or by lattice vibrations? A nano-contact experiment shows that on a Nb surface friction drops by a factor of three when crossing the superconductivity transition, showing that it has essentially an electronic nature in the metallic state, whereas the phononic contribution dominates in the superconducting state.

Phase-change materials are key components in rewritable optical disks and are promising for non-volatile electronic memories. The very different structure and ultrafast recrystallization dynamics of another class of phase-change materials, Sb–Te-based alloys, now suggests their use in future memory applications.

Actin networks are an excellent model system for studying the mechanical properties of the cell cytoskeleton. Using microscopic methods, actin bundle networks formed in the presence of the crosslinking protein fascin show age-dependent changes in their viscoelastic properties and spontaneous relaxation dynamics in a similar way to glassy, soft materials.

Phase-change materials are used in computer memories for their switching between amorphous and crystalline phases. However, even the crystalline state shows disorder, with extremely small electron mean free paths. The discovery that, depending on annealing temperature, this disorder leads to a metal–insulator transition in the crystalline phase provides a completely new look at the transport properties of these compounds.