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Momentum-dependent multiple gaps in magnesium diboride probed by electron tunnelling spectroscopy
The electronic structure of superconducting magnesium diboride is predicted theoretically to have a distribution of energy gap values. Chenet al. observe this distribution of values experimentally, by means of high-resolution electron tunnelling spectroscopy.
- Ke Chen
- , Wenqing Dai
- & X. X. Xi
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Revealing the role of defects in ferroelectric switching with atomic resolution
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
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Magnetic resonance force microscopy of paramagnetic electron spins at millikelvin temperatures
Magnetic resonance force microscopy is a scanning probe technique capable of detecting and imaging electron spins. Vinanteet al.bring the operating temperature of this method into the millikelvin temperature regime, revealing spin diffusion phenomena that were hitherto inaccessible.
- A. Vinante
- , G. Wijts
- & T.H. Oosterkamp
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Three-dimensional high-resolution quantitative microscopy of extended crystals
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
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Towards hybrid superlattices in graphene
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
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| Open AccessA new regime for mechanical annealing and strong sample-size strengthening in body centred cubic molybdenum
Mechanical annealing is a process through which the dislocation density in submicrometre metal crystals can be removed purely by applying a mechanical stress. This study shows that mechanical annealing occurs in body centred cubic molybdenum, and not only in face centred crystals as previously thought.
- Ling Huang
- , Qing-Jie Li
- & Evan Ma
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| Open AccessCoupling artificial molecular spin states by photon-assisted tunnelling
Tunnelling transitions triggered by microwave irradiation between coupled quantum dots have generally been assumed to be spin-conserving. This study shows that this condition is violated in the presence of spin–orbit coupling, thus opening new possibilities for manipulating a two–spin qubit system by microwave irradiation.
- L.R. Schreiber
- , F.R. Braakman
- & L.M.K. Vandersypen
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Functionalized arrays of Raman-enhancing nanoparticles for capture and culture-free analysis of bacteria in human blood
Detecting bacteria in clinical samples usually requires culture processes that are time consuming and impede rapid diagnoses. Now, a surface-enhanced Raman spectroscopic method is reported that allows the label- and culture-free detection and analysis of bacteria.
- Ting-Yu Liu
- , Kun-Tong Tsai
- & Yuh-Lin Wang
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| Open AccessNanomechanical DNA origami 'single-molecule beacons' directly imaged by atomic force microscopy
DNA origami involves the folding of long single-stranded DNA into designed structures that may aid the development of useful nanomechanical DNA devices. In this study, DNA origami pliers and forceps are shown to undergo conformational changes on single-molecule binding.
- Akinori Kuzuya
- , Yusuke Sakai
- & Makoto Komiyama
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| Open AccessMeasuring single-nanoparticle wetting properties by freeze-fracture shadow-casting cryo-scanning electron microscopy
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
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Direct imaging of Joule heating dynamics and temperature profiling inside a carbon nanotube interconnect
The use of carbon nanotubes in nanoelectronics requires an understanding of their resistive, or Joule, heating at interconnects. Here, Joule heating dynamics are imaged in real time by following the evolution of resistive hot spots with a transmission electron microscope.
- Pedro M.F.J. Costa
- , Ujjal K. Gautam
- & Dmitri Golberg
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| Open AccessMesoscale flux-closure domain formation in single-crystal BaTiO3
Flux-closure patterns are rarely observed in ferroelectric materials and almost exclusively form at the nanoscale. McQuaidet al. report mesoscopic dipole closure patterns formed in free-standing single-crystal lamellae of BaTiO3, thought to result from an unusual set of experimental conditions.
- R.G.P. McQuaid
- , L.J. McGilly
- & J.M. Gregg
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Imaging local electronic corrugations and doped regions in graphene
The unoccupied electronic levels of graphene are modified by corrugation, doping and presence of impurities. Here, the authors map discrete electronic domains within a single graphene sheet using scanning transmission X-ray microscopy and provide insight into the modification of unoccupied levels.
- Brian J. Schultz
- , Christopher J. Patridge
- & Sarbajit Banerjee
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| Open AccessDetermination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation
Nanoparticles continue to find research and industrial applications, but no single technique exists to characterise their physical properties. Now, an analytical ultracentrifugation method is described which allows the simulataneous determination of nanoparticle size, density and molecular weight distribution.
- Randy P. Carney
- , Jin Young Kim
- & Osman M. Bakr
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Experimental demonstration of low-loss optical waveguiding at deep sub-wavelength scales
Metal-based nanostructures offer a solution to scale down photonics to the nanoscale. Sorgeret al. directly demonstrate waveguiding of ultra-small propagating waves at visible and near-infrared frequencies using NSOM imaging, with the potential for nanoscale photonic applications such as bio-sensing.
- Volker J. Sorger
- , Ziliang Ye
- & Xiang Zhang
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Synthesis of hexagonal close-packed gold nanostructures
Solid gold is most stable as a face-centred cubic structure, and stable colloidal gold with hexagonal close packing has not been produced. Huanget al.prepare square gold sheets with hexagonal close packing that are stable under ambient conditions.
- Xiao Huang
- , Shaozhou Li
- & Hua Zhang
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Plasmonic beaming and active control over fluorescent emission
Nanometallic optical antennas can concentrate light into a deep-subwavelength volume for sensor and photovoltaic applications. Junet al. demonstrate an optical antenna design that achieves a high level of control over fluorescent emission for a wide range of nanoscale optical spectroscopy applications.
- Young Chul Jun
- , Kevin C.Y. Huang
- & Mark L. Brongersma
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Optical virtual imaging at 50 nm lateral resolution with a white-light nanoscope
Lenses are restricted by diffraction to imaging features roughly the size of visible wavelengths. Wanget al. develop a white-light nanoscope that uses optically transparent spherical silica lenses to virtually image, in the far-field, features down to 50 nm resolution.
- Zengbo Wang
- , Wei Guo
- & Minghui Hong
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Ionic polypeptides with unusual helical stability
Water-soluble peptides with stable α-helical conformations are desirable for a range of applications, but incorporating charged residues to improve solubility usually leads to reduced helical stability. Here, polypeptides produced from amino acids with elongated charged side chains are found to be water soluble and exhibit very high helical stability.
- Hua Lu
- , Jing Wang
- & Jianjun Cheng
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Three-dimensional imaging of magnetic domains
The imaging of magnetic domains in three-dimensional solids has been hampered by a lack of suitable methods. The authors show that Talbot-Lau neutron tomography is capable of visualizing the domain structure of an iron silicide bulk crystal.
- I. Manke
- , N. Kardjilov
- & J. Banhart
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Piezoelectric-nanowire-enabled power source for driving wireless microelectronics
Energy harvesting through mechanical actions of nanosized components could be useful for powering mobile electronics. Here, the authors grow lead zirconate nanowire arrays at comparatively low temperature and use them to power a macroscopic laser diode.
- Sheng Xu
- , Benjamin J. Hansen
- & Zhong Lin Wang
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One-by-one trap activation in silicon nanowire transistors
Flicker noise in nanoscale field effect transistors deviates from the simple frequency-dependent behaviour of macroscale objects. Here the authors show that Coulomb repulsion between nearby trap sites leads to an order of magnitude reduction in noise in these devices.
- N. Clément
- , K. Nishiguchi
- & D. Vuillaume