Nanoscience and technology

  • Letter |

    Thermal transitions of polyisocyanide single molecules to polymer bundles and finally networks lead to hydrogels mimicking the properties of biopolymer intermediate-filament networks; their analysis shows that bundling and chain stiffness are crucial design parameters for hydrogels.

    • Paul H. J. Kouwer
    • , Matthieu Koepf
    •  & Alan E. Rowan
  • Letter |

    An efficient and scalable strategy with robust error correction is reported for encoding a record amount of information (including images, text and audio files) in DNA strands; a ‘DNA archive’ has been synthesized, shipped from the USA to Germany, sequenced and the information read.

    • Nick Goldman
    • , Paul Bertone
    •  & Ewan Birney
  • Letter |

    The hardness, toughness and chemical stability of the well-known superhard material cubic boron nitride have been improved by using a synthesis technique based on specially prepared ‘onion-like’ precursor materials.

    • Yongjun Tian
    • , Bo Xu
    •  & Zhongyuan Liu
  • Letter |

    Topologically distinct colloidal particles introduced into a nematic liquid crystal align and generate topology-constrained three-dimensional director fields and defects in the liquid crystal fluid that can be manipulated with a variety of methods, opening up a new area of exploration in the field of soft matter.

    • Bohdan Senyuk
    • , Qingkun Liu
    •  & Ivan I. Smalyukh
  • Letter |

    Two gold nanostructures with controllable subnanometre separation are used to follow the evolution of plasmonic modes; the distance at which quantum tunnelling sets in is determined, and a quantum limit for plasmonic field confinement is estimated.

    • Kevin J. Savage
    • , Matthew M. Hawkeye
    •  & Jeremy J. Baumberg
  • Letter |

    Controlling the structure of thermoelectric materials on all length scales (atomic, nanoscale and mesoscale) relevant for phonon scattering makes it possible to increase the dimensionless figure of merit to more than two, which could allow for the recovery of a significant fraction of waste heat with which to produce electricity.

    • Kanishka Biswas
    • , Jiaqing He
    •  & Mercouri G. Kanatzidis
  • Letter |

    The AWARE-2 camera uses a parallel array of microcameras to capture one-gigapixel images at three frames per minute.

    • D. J. Brady
    • , M. E. Gehm
    •  & S. D. Feller
  • Letter |

    Propagating cracks—normally associated with material failure and viewed as undesirable—can be controlled in a film/substrate system, opening up new possibilities for nanofabrication and atomic-scale patterning.

    • Koo Hyun Nam
    • , Il H. Park
    •  & Seung Hwan Ko
  • Letter |

    An electron tomography method is demonstrated that can determine the three-dimensional structure of a gold nanoparticle at 2.4 Å resolution, including the locations of some of the individual atoms within the sample.

    • M. C. Scott
    • , Chien-Chun Chen
    •  & Jianwei Miao
  • Article |

    Metal nanoparticles with dimensions below ten nanometres exhibit plasmon resonances governed by quantum mechanical effects, as probed with electron microscopy and spectroscopy

    • Jonathan A. Scholl
    • , Ai Leen Koh
    •  & Jennifer A. Dionne
  • Letter |

    Experiments using ultrafast mid-infrared light pulses on nanostructures access a new regime in photoelectron emission, revealing classical sub-cycle electron dynamics in optical near-fields and breaking a diffraction limit in strong-field physics.

    • G. Herink
    • , D. R. Solli
    •  & C. Ropers
  • Letter |

    A new family of resonators for nanoscale lasers is described that allows the size of the laser cavity to be scaled down without increasing the threshold power required to drive lasing.

    • M. Khajavikhan
    • , A. Simic
    •  & Y. Fainman
  • Letter |

    Use of nanomechanical resonators has the potential to offer microwave amplification with the minimum possible added noise, namely that due to quantum fluctuations.

    • F. Massel
    • , T. T. Heikkilä
    •  & M. A. Sillanpää
  • Letter |

    Use of a three-level system allows the Toffoli gate, an important primitive for quantum error correction schemes, to be implemented with many fewer elementary gates than was previously thought possible.

    • A. Fedorov
    • , L. Steffen
    •  & A. Wallraff
  • Letter |

    Scanning probe techniques such as atomic force microscopy can be readily harnessed to prepare nanoscale structures with exquisite resolution, but are not in general suited for high-throughput patterning. Techniques based on contact printing, on the other hand, offer high throughput over large areas, but can't compete on resolution. Now, an approach is described that offers the best of both worlds: by attaching an array of hard, scanning-probe-like silicon tips to a flexible elastomeric substrate (similar to those used in contact printing), it is possible to rapidly create arbitrary patterns with sub-50-nm resolution over centimetre-scale areas.

    • Wooyoung Shim
    • , Adam B. Braunschweig
    •  & Chad A. Mirkin
  • Letter |

    Many biomineralized tissues (such as teeth and bone) are hybrid inorganic–organic materials whose properties are determined by their convoluted internal structures. Now, using a chiton tooth as an example, this study shows how the internal structural and chemical complexity of such biomaterials and their synthetic analogues can be elucidated using pulsed-laser atom-probe tomography.

    • Lyle M. Gordon
    •  & Derk Joester
  • Letter |

    A potential route to enhancing the performance of electronic devices is to integrate compound semiconductors, which have superior electronic properties, within silicon, which is cheap to process. These authors present a promising new concept to integrate ultrathin layers of single-crystal indium arsenide on silicon-based substrates with an epitaxial transfer method borrowed from large-area optoelectronics. With this technique, the authors fabricate thin-film transistors with excellent device performance.

    • Hyunhyub Ko
    • , Kuniharu Takei
    •  & Ali Javey
  • Letter |

    Quantum entanglement is one of the key resources required for quantum computation. In superconducting devices, two-qubit entangled states have been used to implement simple quantum algorithms, but three-qubit states, which can be entangled in two fundamentally different ways, have not been demonstrated. Here, however, three superconducting phase qubits have been used to create and measure these two entangled three-qubit states.

    • Matthew Neeley
    • , Radoslaw C. Bialczak
    •  & John M. Martinis
  • Letter |

    There is much interest in graphene for applications in ultrahigh-speed radio-frequency electronics, but conventional device fabrication processes lead to significant defects in graphene. Here a new way of fabricating high-speed graphene transistors is described. A nanowire with a metallic core and insulating shell is placed as the gate electrode on top of graphene, and source and drain electrodes are deposited through a self-alignment process, causing no appreciable damage to the graphene lattice.

    • Lei Liao
    • , Yung-Chen Lin
    •  & Xiangfeng Duan
  • Letter |

    Advances in nanomagnetics research have brought powerful applications in magnetic sensing technology, but so far no high-resolution magnetic-imaging tool is available to characterize complex, often buried, nanoscale structures. These authors have developed a scanning probe technique in which the intense, confined magnetic field of a micromagnetic probe tip is used to localize the ferromagnetic resonance mode immediately beneath the probe, and demonstrate that they can image magnetic features at a resolution of 200 nm.

    • Inhee Lee
    • , Yuri Obukhov
    •  & P. Chris Hammel
  • Letter |

    Metamaterials have the counterintuitive optical property of negative refraction index. They have a wide range of possible applications, including 'invisibility cloaks' and perfect lenses, but their performance is severely limited by absorption losses. These authors have incorporated an optical gain medium within a metamaterial as a way to compensate the intrinsic loss, and show that optical pumping leads to a significantly improved negative refraction index and figure of merit within the 722–738-nm visible wavelength range.

    • Shumin Xiao
    • , Vladimir P. Drachev
    •  & Vladimir M. Shalaev
  • Letter |

    Topological surface states are a class of electronic states that might be of interest in quantum computing or spintronic applications. They are predicted to be robust against imperfections, but so far there has been no evidence that these states do transmit through naturally occurring surface defects. Here, scanning tunnelling microscopy has been used to show that topological surface states of antimony can be transmitted through naturally occurring barriers that block non-topological surface states of common metals.

    • Jungpil Seo
    • , Pedram Roushan
    •  & Ali Yazdani
  • Letter |

    Light–matter interactions in semiconductors hold great promise for numerous applications, but as device size is reduced such interactions typically weaken, potentially posing problems for applications at the nanoscale. Here the authors circumvent these limitations by producing colloidal particles with metallic cores and semiconducting shells, in which coupling of the plasmons in the metal to the excitons in the semiconductor is engineered to enhance light–matter interactions in the particle.

    • Jiatao Zhang
    • , Yun Tang
    •  & Min Ouyang
  • Letter |

    Many new functional materials and devices could be made if it were possible to rationally combine nanometre-scale particles into larger structures. An assembly line operating on the nanometre scale has now been demonstrated. It uses a DNA origami tile as a framework and track for the assembly process, three distinct DNA machines attached to the tile as programmable cargo-donating devices, and a DNA walker to generate the target product by moving along the track and collecting cargo from those devices that are switched on.

    • Hongzhou Gu
    • , Jie Chao
    •  & Nadrian C. Seeman
  • Letter |

    Supercooling is a phenomenon by which a liquid remains in its fluid phase well below its melting point. Supercooling can be inhibited by the presence of a solid surface, whereby crystalline surfaces cause adjacent atoms in the liquid to become ordered, inducing crystal nucleation of the melt. Here it is shown that a particular surface ordering of gold atoms on top of a silicon substrate can stabilize the liquid phase of a gold-silicon eutectic droplet, and thus enhance supercooling.

    • T. U. Schülli
    • , R. Daudin
    •  & A. Pasturel
  • Letter |

    An imaging technique that could identify all the individual atoms, including defects, in a material would be a useful tool. Here an electron-microscopy approach to the problem, based on annular dark-field imaging, is described. A monolayer of boron nitride was studied, and three types of atomic substitution were identified. Careful analysis of the data enabled the construction of a detailed map of the atomic structure.

    • Ondrej L. Krivanek
    • , Matthew F. Chisholm
    •  & Stephen J. Pennycook
  • Letter |

    Surface-enhanced Raman scattering is a powerful spectroscopy technique that can be used to study substances down to the level of single molecules. But the practical applications have been limited by the need for metal substrates with roughened surfaces or in the form of nanoparticles. Here a new approach — shell-insulated nanoparticle-enhanced Raman spectroscopy — is described, and its versatility demonstrated with numerous test substances.

    • Jian Feng Li
    • , Yi Fan Huang
    •  & Zhong Qun Tian