Physical sciences

  • 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 |

    Exchange bias is a technologically relevant effect that occurs when thin ferromagnetic films are placed in direct proximity to antiferromagnets. Raduet al. show that an exchange bias occurs at room temperature in ferrimagnetic trilayers, in which the magnetization is aligned perpendicular to the structures.

    • F. Radu
    • , R. Abrudan
    •  & H. Zabel
  • 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
  • Review Article |

    High-valent iron–oxo and –nitrido complexes are intermediates in the catalytic cycles of various metalloenzymes that activate dioxygen and dinitrogen. Hohenbergeret al. review the advances in the chemistry of model high-valent iron–oxo and –nitrido systems and relate them to our understanding of related enzymes.

    • Johannes Hohenberger
    • , Kallol Ray
    •  & Karsten Meyer
  • Article
    | Open Access

    Advances in nanoelectromechanical systems have brought improvements in the quality factor of nanomechanical resonators, yet few low-loss transduction schemes exist at high temperature. Using non-dissipative dielectric coupling to a microwave cavity, Faustet al. present an integrated nanomechanical transducer.

    • T. Faust
    • , P. Krenn
    •  & E.M. Weig
  • 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
    | 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 |

    Imaging and tracking the motion of single molecules on cell plasma membranes requires high spatial resolution in three dimensions. Honget al. develop a plasmonic ruler based on the fluorescence enhancement of carbon nanotubes on a gold plasmonic substrate, allowing the observation of nanotube endocytosis in three dimensions.

    • Guosong Hong
    • , Justin Z. Wu
    •  & Hongjie Dai
  • 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
    | Open Access

    Intracellular temperature mapping has not previously been achieved. Now, a fluorescent polymeric thermometer has been developed that can be used in combination with fluorescence-lifetime imaging microscopy to allow thermometry with spatial and temperature resolutions of 200 nm and 0.18–0.58 ° C.

    • Kohki Okabe
    • , Noriko Inada
    •  & Seiichi Uchiyama
  • Article
    | Open Access

    Minimising reflection from the interface between materials is an important goal for optical devices such as solar cells or photodetectors. Spinelliet al. show almost total loss of reflection over a broad spectral range from a silicon surface using periodic arrays of sub-wavelength silicon nanocylinders.

    • P. Spinelli
    • , M.A. Verschuuren
    •  & A. Polman
  • 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 |

    The dynamics of spin ordering in magnetic materials is of interest both from a fundamental and an applied point of view. Using a combination of numerical and experimental techniques, Ostleret al. show that the magnetization of a ferrimagnet can be reversed on a timescale of picoseconds solely by heating it.

    • T.A. Ostler
    • , J. Barker
    •  & A.V. Kimel
  • Article
    | Open Access

    Graphene's broad bandwidth makes it promising as a photodetector, but common electronics cannot analyse the currents at high frequencies. Here, using photocurrent measurements, laser-induced carrier generation effects in freely suspended graphene and at graphene–metal interfaces are clarified up to 1 THz.

    • Leonhard Prechtel
    • , Li Song
    •  & Alexander W. Holleitner
  • 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 |

    Under certain conditions, such as those found in low-dimensional systems, materials can show quantized behaviour based only on universal constants. Here, the relative optical transparency of gold nanopillar arrays is shown to change solely in units of the fine structure constant on adjusting array parameters.

    • V.G. Kravets
    • , F. Schedin
    •  & A.N. Grigorenko
  • 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 |

    The dynamics of isolated quantum systems can either be strongly correlated with their initial state, or chaotic, as they relax into thermal equilibrium. Olshaniiet al. present a simple, exactly solvable model that captures the transition between these two limiting cases, and suggests it may have some universal features.

    • Maxim Olshanii
    • , Kurt Jacobs
    •  & Vladimir A. Yurovsky
  • 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 |

    Dating the age of meteorites can tell us when asteroids formed, but uncertainty remains in the Mn–Cr chronometry. This study presents a method for improving Mn/Cr determination and reports an age of 4,563.4 million years ago for carbonates in CM chondrites, which is younger than previous estimates.

    • Wataru Fujiya
    • , Naoji Sugiura
    •  & Yuji Sano
  • Article |

    Single-photon emitters are important for developing quantum technologies, but their integration with existing devices requires them to be driven by electric fields. Here, an organic light-emitting diode is presented that emits single photons from guest molecules in an applied electric field at room temperature.

    • Maximilian Nothaft
    • , Steffen Höhla
    •  & Jörg Wrachtrup
  • Article
    | Open Access

    Although they offer significant promise, practical implementations of quantum key distribution are often not as rigorous as theory predicts. This study demonstrates how two instances of such discrepancies can be resolved by taking advantage of an enotropic formulation of the uncertainty principle.

    • Marco Tomamichel
    • , Charles Ci Wen Lim
    •  & Renato Renner
  • Article
    | Open Access

    Untrustworthy sources or detectors mean that quantum entanglement cannot always be ensured, but quantum steering inequalities can verify its presence. Using a highly efficient system, Smithet al. are able to close the detection loophole and clearly demonstrate steering between two parties.

    • Devin H. Smith
    • , Geoff Gillett
    •  & Andrew G. White
  • Article |

    A dual-contrast agent has been developed for combined ultrasound and photoacoustic imaging. This agent uses vaporization for ultrasound contrast enhancement and photoacoustic signal generation, providing significantly higher signals than thermal expansion, the most commonly used photoacoustic mechanism.

    • Katheryne Wilson
    • , Kimberly Homan
    •  & Stanislav Emelianov
  • 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

    Quantum mechanics predicts that objects can simultaneously exist in a superposition of two states. Kneeet al.propose and demonstrate experimentally a protocol which fully confirms this prediction, by testing the so-called Leggett–Garg inequality in a non-invasive manner.

    • George C. Knee
    • , Stephanie Simmons
    •  & Simon C. Benjamin
  • Article
    | Open Access

    Fluctuations of the electrical current in nanoscale devices reveal important details of the physical processes occurring inside them. Using a quantum point contact placed in its vicinity, Ubbelohde et al. measure the electrical fluctuations in a single-electron transistor, and determine the dynamical features of the transport.

    • Niels Ubbelohde
    • , Christian Fricke
    •  & Rolf J. Haug
  • 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