Physical sciences

  • Article
    | Open Access

    Stimulus-responsive hydrogels have previously been developed that display heat-, light-, pH- or redox-induced sol–gel transitions. Nakahataet al. develop a self-healing supramolecular hydrogel based on host–guest polymers in which redox potential can induce a reversible sol–gel phase transition.

    • Masaki Nakahata
    • , Yoshinori Takashima
    •  & Akira Harada
  • Article |

    Intercalating alkali metals into picene—a hydrocarbon with five linearly fused benzene rings—results in superconducting materials. Now, alkali-metal-doped phenanthrene, which consists of three fused benzene rings, is also found to be superconducting, opening up a broader class of organic superconductors.

    • X.F. Wang
    • , R.H. Liu
    •  & X.H. Chen
  • Article
    | Open Access

    In the theory of general relativity time flows at different rates depending on the space–time geometry. Here, a drop in the visibility of a quantum 'clock' interference in a gravitational potential is predicted, which cannot be explained without the general relativistic notion of time.

    • Magdalena Zych
    • , Fabio Costa
    •  & Časlav Brukner
  • Article |

    Nanofluidic diodes are utilized for the rectification of ionic transport, but their rectifying properties cannot be altered after the devices are made. Here, a field-effect reconfigurable nanofluidic diode is reported in which the forward direction and the degree of rectification can be modulated by a gate voltage.

    • Weihua Guan
    • , Rong Fan
    •  & Mark A. Reed
  • Article |

    Hoop-shaped aromatic hydrocarbons can be considered as finite models of single-wall carbon nanotubes. Hitosugiet al. describe the bottom-up synthesis of a macrocyclic tetramer of chrysene, and show that its persistent rotational isomers are finite models of chiral nanotubes.

    • Shunpei Hitosugi
    • , Waka Nakanishi
    •  & Hiroyuki Isobe
  • Article |

    Molecular probes that can detect aqueous sulphides could help to elucidate their roles in biological signalling. Qianet al. develop two sulphide-selective fluorescent probes and demonstrate their ability to image free sulphide in living cells.

    • Yong Qian
    • , Jason Karpus
    •  & Chuan He
  • Article |

    The ability to control the charge and spin of single molecules at metal interfaces underpins the concept of molecular electronics. Mugarzaet al. examine these properties using scanning tunnelling microscopy, and uncover their influence on the magnetism and transport properties of the molecule/metal systems.

    • Aitor Mugarza
    • , Cornelius Krull
    •  & Pietro Gambardella
  • Article |

    Simple routes to self-assembling magnetic materials are elusive. Tew and colleagues produce copolymers containing cobalt complexes, which phase separate to give ferromagnetic properties at room temperature following heat treatment.

    • Zoha M. AL-Badri
    • , Raghavendra R. Maddikeri
    •  & Gregory N. Tew
  • Article
    | Open Access

    Nanocrystals are used in light-emitting diodes and solar cells, but their charge transport in films is unclear. Here, the study of PbS nanocrystal films reveals the role of mid-gap states in their charge transport, suggesting different design needs for devices operated in dark (transistors) versus light (solar cells) conditions.

    • Prashant Nagpal
    •  & Victor I. Klimov
  • Article
    | Open Access

    Advanced biofuels with comparable properties to petroleum-based fuels could be microbially produced from lignocellulosic biomass. In this study,Escherichia coliis engineered to produce bisabolene, the immediate precursor of bisabolane, a biosynthetic alternative to D2 diesel.

    • Pamela P. Peralta-Yahya
    • , Mario Ouellet
    •  & Taek Soon Lee
  • Article
    | Open Access

    Spin ices are magnetic materials in which excitations equivalent to monopoles can occur. Using high-pressure techniques, Zhouet al. synthesize a new member of the spin ice family, Dy2Ge2O7, in which monopoles exist at higher densities, and can stabilize as dimers.

    • H.D. Zhou
    • , S.T. Bramwell
    •  & J.S. Gardner
  • Article |

    Quasi-three-dimensional plasmonic crystals have potential uses in miniaturized photonics. In this study, a method is described to enhance plasmonic resonance in the crystals by coupling them to optical modes of Fabry–Perot type cavities, with possible applications in photonic and sensor components.

    • Debashis Chanda
    • , Kazuki Shigeta
    •  & John A. Rogers
  • Article
    | Open Access

    Plasmon resonances occur as collective excitations of surface electrons in noble metal nanoparticles. This study presents a new way of manipulating their behaviour by creating bimetallic dimers which, as a result of their asymmetric composition, give rise to unusual optical properties.

    • Timur Shegai
    • , Si Chen
    •  & Mikael Käll
  • Article |

    The manipulation of electrons forms the basis of modern technology, whereas electrical signalling processes in nature are based on ions and protons. Rolandi and colleagues present a proton transistor based on polysaccharide nanofibres, which can control the flow of protonic currents.

    • Chao Zhong
    • , Yingxin Deng
    •  & Marco Rolandi
  • Article
    | Open Access

    Inertial sensors using atom interferometry have applications in geophysics, navigation- and space-based tests of fundamental physics. Here, the first operation of an atom accelerometer during parabolic flights is reported, demonstrating high-resolution measurements at both 1g and 0g.

    • R. Geiger
    • , V. Ménoret
    •  & P. Bouyer
  • Article
    | Open Access

    Transparent conducting oxides are wide bandgap conductors that have found a range of applications in optoelectronic devices. In this study, Hosono and colleagues fabricate the first transparent conducting oxide based on germanium.

    • Hiroshi Mizoguchi
    • , Toshio Kamiya
    •  & Hideo Hosono
  • Article |

    Plasmonic nanostructures can be used to manipulate objects larger than the wavelength of light but create thermal heating. In this work, the trapping and controlled rotation of nanoparticles is demonstrated using a plasmonic nanotweezer with a heat sink, predicting a reduction in heating compared with previous designs.

    • Kai Wang
    • , Ethan Schonbrun
    •  & Kenneth B. Crozier
  • Article
    | Open Access

    The paradigm of reservoir computing shows that, like the human brain, complex networks can perform efficient information processing. Here, a simple delay dynamical system is demonstrated that can efficiently perform computations capable of replacing a complex network in reservoir computing.

    • L. Appeltant
    • , M.C. Soriano
    •  & I. Fischer
  • Article |

    Protein microarrays are useful both in basic research and also in disease monitoring and diagnosis, but their dynamic range is limited. By using plasmonic gold substrates with near-infrared fluorescent enhancement, Tabakman et al. demonstrate a multiplexed protein array with improved detection limits and dynamic range.

    • Scott M. Tabakman
    • , Lana Lau
    •  & Hongjie Dai
  • Article |

    It is unclear whether the Fermi surface in the normal state of underdoped cuprates is ambipolar or solely nodal. Here, measuring the second harmonic oscillations in underdoped YBa2Cu3O6+xreveals the origin as an oscillatory chemical potential, based on which a Fermi surface consisting of a nodal pocket is identified.

    • Suchitra E. Sebastian
    • , N. Harrison
    •  & G.G. Lonzarich
  • Article |

    Hydrogels have a variety of applications including tissue engineering and controlled drug delivery. Here, liquid-crystal hydrogels are developed which transform into a fluid solution upon cooling; cells can be encapsulated in the gel at room temperature, then released at physiological temperatures.

    • Zhegang Huang
    • , Hyojin Lee
    •  & Myongsoo Lee
  • Article |

    Property coupling by heteroepitaxy is severely limited in material combinations with highly dissimilar bonding. This report presents a chemical boundary condition methodology to actively engineer two-dimensional film growth in such systems that otherwise collapse into island formation and rough morphologies.

    • Elizabeth A. Paisley
    • , Mark. D. Losego
    •  & Jon-Paul Maria
  • Article |

    Quadrupoles have many engineering applications, but experimental observations of fluidic multipoles have not been reported. This study presents an experimental two-dimensional microfluidic quadrupole, a theoretical analysis consistent with observations, and a first application as a channel-free floating gradient generator.

    • Mohammad A. Qasaimeh
    • , Thomas Gervais
    •  & David Juncker
  • Article
    | Open Access

    The measurement of the total cross-section of proton–proton collisions is of fundamental importance for particle physics. Here, the first measurement of the inelastic cross-section is presented for proton–proton collisions at an energy of 7 teraelectronvolts using the ATLAS detector at the Large Hadron Collider.

    • G. Aad
    • , B. Abbott
    •  & L. Zwalinski
  • Article |

    Photodetection is believed to be among the most promising potential applications for graphene. Here, by combining graphene with plasmonic nanostructures, the efficiency of graphene-based photodetectors is increased by up to two orders of magnitude.

    • T.J. Echtermeyer
    • , L. Britnell
    •  & K.S. Novoselov
  • Article
    | Open Access

    Cell-penetrating peptides can deliver molecular cargoes into living cells, and cross biological membranes by transduction—a non-endocytic mechanism. Here, the transduction efficiency of cyclic arginine-rich peptides is shown to be higher than that of more flexible linear peptides.

    • Gisela Lättig-Tünnemann
    • , Manuel Prinz
    •  & M. Cristina Cardoso
  • Article
    | Open Access

    Various methods have been investigated to locally control atmospheric precipitation. In this study, field experiments show that laser-induced condensation is initiated when the relative humidity exceeds 70%, and that this effect is largely a result of photochemical HNO3formation.

    • S. Henin
    • , Y. Petit
    •  & J.-P. Wolf
  • Article
    | Open Access

    Determining the direction of the magnetic field of light is important for optical applications. Here, scattering of light from a subwavelength aperture in a metal plane is shown to be governed by its magnetic vector, providing the magnetic field orientation independently of the electric field.

    • H.W. Kihm
    • , S.M. Koo
    •  & D.-S. Kim
  • Article |

    Multiple scattering complicates femtosecond optics such that phase conjugation allows spatial focusing and imaging through a multiple scattering medium, but temporal control is problematic. McCabeet al. report the full spatio-temporal characterization and recompression of a femtosecond speckle field.

    • David J. McCabe
    • , Ayhan Tajalli
    •  & Béatrice Chatel
  • Article
    | Open Access

    At extreme temperature and pressure, materials can form new dense phases with unusual physical properties. Here, laser-induced microexplosions are used to produce a superdense, stable, body-centred-cubic form of aluminium, which was previously predicted to exist at pressures above 380GPa.

    • Arturas Vailionis
    • , Eugene G. Gamaly
    •  & Saulius Juodkazis
  • Article
    | Open Access

    High-power mechanical energy harvesting could be an alternative to batteries, but efficient energy conversion technology has been missing. Here, a novel mechanical-to-electrical energy conversion method is described that is based on reverse electrowetting and is uniquely suited for high-power energy harvesting.

    • Tom Krupenkin
    •  & J. Ashley Taylor
  • Article |

    The development of practical photonic quantum technologies will be aided by the spatial control of entangled photons. Lenget al. achieve on-chip spatial control of entangled photons by using domain engineering, rather than by using external optical elements.

    • H.Y. Leng
    • , X.Q. Yu
    •  & S.N. Zhu
  • Article |

    Composites of carbon nanotubes and superconductors provide technologically important new, or improved, functionalities. Here, with a chemical solution approach, well-aligned carbon nanotube forests embedded in a superconducting NbC matrix are shown to effectively enhance the superconducting properties of NbC.

    • G.F. Zou
    • , H.M. Luo
    •  & Q.X. Jia
  • Article
    | Open Access

    Being able to determine the wetting properties of individual nanoparticles would aid the preparation of particles with controlled surface properties. Isaet al. develop an in situ freeze-fracture shadow-casting method and use this to determine structural and thermodynamic properties of various 10 nm particles at fluid interfaces.

    • Lucio Isa
    • , Falk Lucas
    •  & Erik Reimhult
  • Article
    | Open Access

    An electron pocket exists in the Fermi-surface of the high temperature superconductor YBa2Cu3Oy, but its origin is unknown. Here, YBa2Cu3Oy and La1.8−xEu0.2SrxCuO4 are both shown to exhibit Fermi-surface reconstruction, and in the latter, this is due to stripe order, suggesting that the same mechanism exists in YBa2Cu3Oy.

    • F. Laliberté
    • , J. Chang
    •  & Louis Taillefer
  • Article
    | Open Access

    Single atoms can be detected using optical resonators that extend the lifetime of the photon. Here, the authors demonstrate fast, high-fidelity detection of very low atom densities using a microfabricated optical cavity to couple the detection light with the atoms.

    • J. Goldwin
    • , M. Trupke
    •  & E.A. Hinds
  • Article
    | Open Access

    Magnesium is an ideal rechargeable battery anode material, but coupling it with a low-cost sulphur cathode, requires a non-nucleophilic electrolyte. Kimet al. prepare a non-nucleophilic electrolyte from hexamethyldisilazide magnesium chloride and aluminium trichloride, and show its compatibility with a sulphur cathode.

    • Hee Soo Kim
    • , Timothy S. Arthur
    •  & John Muldoon
  • Article |

    Ferromagnetic systems produced by the transition metal doping of semiconductors may be used as components of spintronic devices. Here, a new ferromagnet, Li1+y(Zn1-xMnx)As, is prepared in bulk quantities and shown to have a critical temperature approaching 50 K.

    • Z. Deng
    • , C.Q. Jin
    •  & Y.J. Uemura
  • Article
    | Open Access

    Chemical manipulation of fullerenes has allowed the production of heptagon-containing fullerenes, but they have not been synthesised using bottom-up approaches. Here, a heptagon-containing fullerene[68] is obtained as C68Cl6from a carbon arc plasma.

    • Yuan-Zhi Tan
    • , Rui-Ting Chen
    •  & Lan-Sun Zheng