Materials science

  • Article
    | Open Access

    Point defects in diamond in the form of nitrogen vacancy centres are believed to be promising candidates for qubits in quantum computers. Grotzet al. present a method for manipulating the charge state of nitrogen vacancies using an electrolytic gate electrode.

    • Bernhard Grotz
    • , Moritz V. Hauf
    •  & Jose A. Garrido
  • Article |

    Organic electronic devices are promising for many applications, particularly in biomedical research, but are hindered by thermal instability and low melting points. Now, organic thin-film transistors are shown with excellent thermal properties that can withstand medical sterilization processes.

    • Kazunori Kuribara
    • , He Wang
    •  & Takao Someya
  • Article |

    Teflon is a carbon based polymer that cannot be intrinsically ferromagnetic. This study shows that room temperature ferromagnetism can be induced in Teflon tape by applying mechanical stress such as stretching or cutting, which gives rise to dangling carbon bonds.

    • Y.W. Ma
    • , Y.H. Lu
    •  & J. Ding
  • Article
    | Open Access

    Biological materials efficiently exploit self-assembly of simple constituents to produce complex functional structures such as optical devices. By controlling organic molecules, Leeet al. show fast two-step self-assembly of CaCO3microlens arrays, reminiscent of their biological counterparts.

    • Kyubock Lee
    • , Wolfgang Wagermaier
    •  & Peter Fratzl
  • Article
    | Open Access

    Multicompartment micelles can be assembled from block copolymers but it is difficult to manipulate their hierarchical superstructures using straightforward concepts. Here, methods are developed that involve the pre-assembly of subunits for the structurally controlled production of micelles.

    • André H. Gröschel
    • , Felix H. Schacher
    •  & Axel H.E. Müller
  • Article
    | Open Access

    Grain boundaries in graphene degrade its properties, and large single-crystal graphene is desirable for electronic applications of graphene. Gaoet al. develop a method to produce millimetre-sized hexagonal single-crystal graphene grains, and films composed of the grains, on platinum by chemical vapour deposition.

    • Libo Gao
    • , Wencai Ren
    •  & Hui-Ming Cheng
  • Article |

    Light-emitting diodes in the form of nanocrystals offer promise for environmental and biomedical diagnostics. Brovelliet al. present a method for realizing mechanically robust and chemically stable nanocrystals emitting light in the ultraviolet range.

    • Sergio Brovelli
    • , Norberto Chiodini
    •  & Alberto Paleari
  • Article |

    Tuning the bandgap of complex transition metal oxides in a manner that preserves their intrinsic properties has so far remained elusive. Choiet al. demonstrate that the bandgap of bismuth titanate can be varied by substitutional alloying with lanthanum cobaltate, without altering its ferroelectric properties.

    • Woo Seok Choi
    • , Matthew F. Chisholm
    •  & Ho Nyung Lee
  • Article |

    The spin–orbit interaction affects the electronic structure of many solids to give rise to a host of unusual phenomena. Bahramyet al.theoretically examine its role in the non-centrosymmetric compound BiTeI, and find that under the application of pressure, it leads to topologically insulating behaviour.

    • M.S. Bahramy
    • , B.-J. Yang
    •  & N. Nagaosa
  • Article
    | Open Access

    Field-effect transistors fabricated from carbon nanotubes have been investigated extensively over the past two decades. This study demonstrates a nanotube-based integrated circuit design that substantially improves the speed and power consumption with respect to silicon-based integrated circuits.

    • Li Ding
    • , Zhiyong Zhang
    •  & Lian-Mao Peng
  • Article |

    Strategies to tune the surface properties of topological insulators are essential, if they are to find use in applications. Using a combination of theoretical and experimental techniques, this study examines how the properties of ordered ternary topological insulators vary with the content of group IV elements.

    • Sergey V. Eremeev
    • , Gabriel Landolt
    •  & Evgueni V. Chulkov
  • Article |

    The surface electronic structure of topological insulators is characterized by a so-called Dirac cone energy dispersion. This study shows that by tuning the compositions in the compound Bi2−xSbxTe3−ySeyone can control the precise features of its Dirac cone structure while keeping it a bulk insulator.

    • T. Arakane
    • , T. Sato
    •  & Yoichi Ando
  • Article |

    Current methods for fabricating graphene rely on its transfer from metal surfaces to substrates suitable for device applications. This study demonstrates a transfer-free approach for growing graphene on substrates such as thermally oxidized silicon and plastic that forms the material underneath a nickel film, at the nickel–substrate interface.

    • Jinsung Kwak
    • , Jae Hwan Chu
    •  & Soon-Yong Kwon
  • Article
    | Open Access

    The spin Hall effect is a spin current induced by an electric current, and its occurrence in semiconductors is a promising route to controlling spins and their transport. Here, the inverse spin Hall effect, in which an electric current is induced by a spin current, is observed in silicon for the first time.

    • Kazuya Ando
    •  & Eiji Saitoh
  • Article |

    The mechanism through which ice forms on surfaces is of broad technological relevance. This study examines the manner in which ice forms on so-called 'icephobic' surfaces, and demonstrates that simple changes in the environmental conditions can render the icephobicity ineffective.

    • Stefan Jung
    • , Manish K. Tiwari
    •  & Dimos Poulikakos
  • Article
    | Open Access

    Self-assembly through molecular recognition events is used in the production of functionalized materials. This study shows that macroscopic gel assembly can be regulated through photoisomerization of an azobenzene moiety that interacts differently with two host molecules.

    • Hiroyasu Yamaguchi
    • , Yuichiro Kobayashi
    •  & Akira Harada
  • Article
    | Open Access

    The elastic limit represents the maximum stress and strain a material can withstand and is well characterized in many crystalline solids, yet remains elusive for metallic glasses. Here, this limit is investigated in submicron metallic glass structures and is found to be twice as high as that of bulk samples.

    • Lin Tian
    • , Yong-Qiang Cheng
    •  & Evan Ma
  • Article |

    Ferroelectric materials are characterized by a spontaneous polarization, which in practical applications is manipulated by an electric field. This study examines how defects affect the switching with atomic resolution, by usingin situaberration-corrected transmission electron microscopy.

    • Peng Gao
    • , Christopher T. Nelson
    •  & Xiaoqing Pan
  • Article
    | Open Access

    Studying carrier multiplication in materials is important to understand their transport properties and interaction with light. Hiroriet al. show that intense terahertz pulses can generate electron-hole pairs in GaAs quantum wells that then emit infrared light, contrary to the effect with a DC field.

    • H. Hirori
    • , K. Shinokita
    •  & K. Tanaka
  • Article |

    When materials change temperature as a result of the application of pressure or a change in the magnetization, they are said to display a barocaloric or magnetocaloric effect, respectively. This study reports a substantial barocaloric effect in the giant magnetocaloric material LaFe11.33Co0.47Si1.2.

    • Lluís Mañosa
    • , David González-Alonso
    •  & Subham Majumdar
  • Article
    | Open Access

    Prenucleation clusters have been observed during the early stages of calcium carbonate formation, contrary to classical models. Here, computer simulations indicate that the clusters are composed of an ionic polymer with alternating calcium and carbonate ions, and a dynamic topology of chains, branches and rings.

    • Raffaella Demichelis
    • , Paolo Raiteri
    •  & Denis Gebauer
  • Article |

    Optical vortex traps are appealing for handling delicate particles, but conventional techniques are challenging with objects smaller than the diffraction limit of light. By exploiting plasmonic resonances in gold diabolo nanoantennas, Kanget al. demonstrate low-power vortex trapping of nano-scale objects.

    • Ju-Hyung Kang
    • , Kipom Kim
    •  & Hong-Gyu Park
  • Article
    | Open Access

    Biomass-derived monomers are a renewable resource for the production of polymers. Robertet al. develop an auto-tandem catalytic transformation for the synthesis of aliphatic polyesters—'activated' monomers are prepared from dicarboxylic acids, which can be copolymerized with epoxides.

    • Carine Robert
    • , Frédéric de Montigny
    •  & Christophe M. Thomas
  • Article |

    The unique band structure of topological insulators gives rise to insulating bulk and unusual metallic surface properties. By tuning the content of Sb in the ternary compound (Bi1–xSbx)2Te3, Wang and collaborators show it is possible to control the precise features of the band structure in a continuous fashion.

    • Jinsong Zhang
    • , Cui-Zu Chang
    •  & Yayu Wang
  • Article |

    Unlike the other iron-based superconductors, the parent compounds of the alkaline iron selenide superconductors are insulators. Dai and colleagues examine the spin-wave excitations in these materials and uncover evidence for a common magnetic origin for all iron-based superconductors.

    • Miaoyin Wang
    • , Chen Fang
    •  & Pengcheng Dai
  • Article
    | Open Access

    Chiral liquid crystals of two-dimensional colloids have not been extensively investigated. Xu and Gao show that graphene oxide can form chiral liquid crystals, and demonstrate that they can be spun into macroscopic fibres, and that subsequent chemical reduction provides graphene fibres with high conductivity.

    • Zhen Xu
    •  & Chao Gao
  • Article |

    Among the wide range of potential applications of graphene, photodetection is believed to be among the most promising. By combining graphene with plasmonic nanostructures, Duan and colleagues observe dramatic improvements in the efficiency and spectral sensitivity of graphene-based photodetectors.

    • Yuan Liu
    • , Rui Cheng
    •  & Xiangfeng Duan
  • Article
    | Open Access

    Topological insulators are a unique class of materials characterized by exotic metallic states at their surface, while remaining insulated in the bulk. Sacépéet al. show how to manipulate normal and superconducting electronic transport at the surface of the topological insulator Bi2Se3, by tuning a gate-voltage to vary the electronic density.

    • Benjamin Sacépé
    • , Jeroen B. Oostinga
    •  & Alberto F. Morpurgo
  • Article |

    Charge density waves in the structure and electron density of layered materials are closely linked to superconductivity. Using scanning tunnelling techniques, Rahnejatet al. demonstrate the occurrence of such waves in the doped graphene sheets of the superconductor CaC6.

    • K.C. Rahnejat
    • , C.A. Howard
    •  & M. Ellerby
  • Article |

    X-ray ptychography has been used to extend the field of view in high-resolution quantitative imaging. Godardet al. develop Bragg-mode ptychography to reconstruct, in three dimensions, a crystalline specimen that is too large to be studied as a single object with a coherence-limited X-ray beam.

    • P. Godard
    • , G. Carbone
    •  & V. Chamard
  • Article
    | Open Access

    The propagation of magnetic domain walls in nanowires offers promise as the basis of future memory storage technologies. Muñoz and Prieto show that the random pinning of domain walls to structural defects in the nanowires can be suppressed at low fields, thus improving the reliability of the transmission of the domain walls substantially.

    • Manuel Muñoz
    •  & José L. Prieto
  • Article |

    The controllable modification of graphene by chemical functionalization can modulate its optical and electronic properties. Sunet al. devise a functionalisation-based method to pattern graphane/graphene superlattices within a single sheet of graphene.

    • Zhengzong Sun
    • , Cary L. Pint
    •  & James M. Tour
  • Article |

    Magnetoelectric materials combine ferroelectric and magnetic properties through a coupling of the spin and lattice degrees of freedom. Here, magnetoelectric bismuth ferrite is found to simultaneously undergo both a magnetic and a ferroelectric transition at the same temperature.

    • Kyung-Tae Ko
    • , Min Hwa Jung
    •  & Chan-Ho Yang
  • Article |

    Batteries that operate at high power and cycling efficiencies could facilitate the development of large-scale energy storage systems. Wessellset al.report a metal–organic framework electrode that operates in an inexpensive aqueous electrolyte with excellent capacity retention over a very large number of cycles.

    • Colin D. Wessells
    • , Robert A. Huggins
    •  & Yi Cui
  • Article
    | Open Access

    Covalent organic frameworks form a porous skeleton with a precise pore size and geometry, but control of the pore surface is challenging. Here, a protocol is introduced for pore surface engineering of covalent organic frameworks, allowing the control of composition and density of organic groups in the pores.

    • Atsushi Nagai
    • , Zhaoqi Guo
    •  & Donglin Jiang
  • Article |

    DNA nanotubes could be used to transport nano-cargo and incorporated into nano-devices. In this study, rolling circle amplification is used to generate DNA subunits, and their thermodynamic growth results in the formation of nanotubes with a controlled diameter.

    • Ofer I. Wilner
    • , Ron Orbach
    •  & Itamar Willner