Characterization and analytical techniques

  • Article
    | Open Access

    Experimental measurements involving multiple laser and plasma parameters are useful in understanding the relativistic laser-plasma interactions. Here the authors extend the model of holeboring for arbitrary profiles of laser pulse and plasma scale lengths.

    • J. Hornung
    • , Y. Zobus
    •  & V. Bagnoud
  • Article
    | Open Access

    A travelling wave inside a metal slit can reveal its own waveform by probing deflecting motions of charged particles. Here, a real-time THz oscilloscope was demonstrated by utilizing the relativistic electrons and the subwavelength slit waveguide.

    • In Hyung Baek
    • , Hyun Woo Kim
    •  & Young Uk Jeong
  • Article
    | Open Access

    Aqueous Zn metal batteries are a promising system for high-power electrochemical energy storage. Here, the authors investigate a defective V2O3 cathode via neutron and X-ray techniques and test the material in Zn metal cell configuration for 30k cycles.

    • Kefu Zhu
    • , Shiqiang Wei
    •  & Li Song
  • Article
    | Open Access

    Morphology of organic thin film, including the in-plane and out-of-plane directions, plays a crucial role in determining the performance of organic solar cells, yet the characterisation is challenging for the out-of-plane direction. Here, the authors use GTSAXS to uncover the nanomorphology in this dimension, and show how it affects exciton dissociation and charge transfer.

    • Xinxin Xia
    • , Tsz-Ki Lau
    •  & Xinhui Lu
  • Article
    | Open Access

    Skyrmions, a topological spin texture, have been found in a variety of magnetic systems, including quantum hall ferromagnets. Here, Yang et al demonstrate the existence of skyrmions in domain walls in a quantum Hall ferromagnet, and suggest that these skyrmions form a 1D Wigner crystal.

    • Kaifeng Yang
    • , Katsumi Nagase
    •  & Hongwu Liu
  • Article
    | Open Access

    Characterizing an unknown, complex system, like an accelerator, in multi-dimensional space is a challenging task. Here the authors report a Bayesian active learning method - Constrained Proximal Bayesian Exploration - for the characterization of a complex, constrained measurement as a function of multiple free parameters.

    • Ryan Roussel
    • , Juan Pablo Gonzalez-Aguilera
    •  & Auralee Edelen
  • Article
    | Open Access

    Free carriers and electrical polarization coexist in ferroelectric metals. Here, the authors use a capacitive method to probe the electronic compressibility of free carriers in a tunable semimetal, extract the polarized contribution, and study the carrier dependence of the ferroelectric state.

    • Sergio C. de la Barrera
    • , Qingrui Cao
    •  & Benjamin M. Hunt
  • Article
    | Open Access

    Artificial sodium channels open up the way to new separation technologies but remains highly challenging. In this work, the authors report an artificial sodium-selective ionic device, built on porous crown-ether crystals with a sodium ion selectivity against calcium ions exceeding that one of biological ion channel counterparts.

    • Tingyan Ye
    • , Gaolei Hou
    •  & Jun Gao
  • Article
    | Open Access

    The limited strength of green parts have been a major hurdle in the Binder Jet Additive Manufacturing. Here the authors apply polyethyleneimine binder to print silica sand structures with double the flexural strength of green parts and 8-fold increase in the strength upon reactive infiltration.

    • Dustin B. Gilmer
    • , Lu Han
    •  & Tomonori Saito
  • Article
    | Open Access

    Balances for nanoparticles such as resonating fluid-filled cantilevers usually probe only mass through changes in oscillation frequency. Katsikis and Collis et al. tap information from previously ignored rotational motion to simultaneously measure particle mass and volume.

    • Georgios Katsikis
    • , Jesse F. Collis
    •  & Scott R. Manalis
  • Article
    | Open Access

    Spatiotemporal dynamic of charge carriers is commonly studied with optical or photoconductivity measurements, yet these techniques come with their own limitations. To circumvent these limits, the authors probe the free-carrier diffusion dynamics of microsecond lifetimes via laser-illuminated microwave impedance microscopy.

    • Xuejian Ma
    • , Fei Zhang
    •  & Keji Lai
  • Article
    | Open Access

    Structural and morphological control of crystalline nanoparticles is crucial in heterogeneous catalysis. Applying DFT-assisted solid-state NMR spectroscopy, we determine the surface crystal and electronic structure of Ni2P nanoparticles, unveiling NMR nanocrystallography as an emerging tool in facet-engineered nanocatalysts.

    • Wassilios Papawassiliou
    • , José P. Carvalho
    •  & Andrew J. Pell
  • Article
    | Open Access

    Despite the important role of ligands in designing nanoparticles, directly imaging them on the nanoparticle surface remains a challenge. Here, the authors use atom probe tomography to map the spatial distribution of ligands on nanoparticles and reveal that the interplay between halide and cetrimonium ligands decides the oxidation resistance and shape of Pd nanoparticles.

    • Kyuseon Jang
    • , Se-Ho Kim
    •  & Pyuck-Pa Choi
  • Article
    | Open Access

    The construction of Z-scheme heterostructures is of great significance for realizing efficient photocatalytic water splitting. Here, the authors report an interfacial chemical bond and internal electric field modulated Z-Scheme Sv-ZnIn2S4/MoSe2 photocatalyst for efficient hydrogen evolution.

    • Xuehua Wang
    • , Xianghu Wang
    •  & Zhenjiang Li
  • Article
    | Open Access

    Charge ordering and superconductivity are known to compete in layered cuprates; however, precise real-space characterization of their interplay has been lacking. Here, the authors address this using atomically-resolved cross-sectional scanning tunnelling microscopy and spectroscopy on cryogenically cleaved YBa2Cu3O6.81.

    • Chun-Chih Hsu
    • , Bo-Chao Huang
    •  & Ya-Ping Chiu
  • Article
    | Open Access

    Quantification of Li ions in local area is key to understand the degradation of Li ion batteries. Here the authors report Li compositional gradient evolution in the cathode after charge-discharge cycles using a complementary study via atom probe tomography and scanning transmission electron microscopy.

    • Byeong-Gyu Chae
    • , Seong Yong Park
    •  & Woo Sung Jeon
  • Article
    | Open Access

    Studying the development of silk structure is important for understanding material properties and biomimetics. Here, the authors use ex vivo processing to characterise the stages of silk spinning and identify a consolidation phase where transient water pockets emerge due to multiple factors leading to nanofibril coalescence.

    • Quan Wan
    • , Mei Yang
    •  & Mingying Yang
  • Article
    | Open Access

    Assessing mechanics of nanoporous silicon is challenging, but important for new applications. Here, the authors use non-destructive laser-excited elastic guided waves detected contactless, to study dry and liquid-infused single-crystalline porous silicon, revealing its complex mechanics and significant deviations from bulk silicon.

    • Marc Thelen
    • , Nicolas Bochud
    •  & Patrick Huber
  • Article
    | Open Access

    Nanopores have been used for direct observation of RNA structure in native environments but have limited RNA differentiation capabilities. Here, the authors report on the use of Mycobacterium smegmatis porin A nanopores for the trapping and translocation identification of microRNA, siRNA, tRNA and ribosomal RNA.

    • Yuqin Wang
    • , Xiaoyu Guan
    •  & Shuo Huang
  • Article
    | Open Access

    Creating predictable, controllable nanoparticles relies on a mechanistic understanding of their synthesis. Here, through integrated in situ liquid microscopy and first-principles calculations, the authors elucidate the atomistic details involved in the formation of colloidal core-shell nanoparticles.

    • Wenpei Gao
    • , Ahmed O. Elnabawy
    •  & Miaofang Chi
  • Article
    | Open Access

    In-situ methods are important for investigating the local structure and function in molecular nanostructures but such investigations often involve laborious labeling methods that can disrupt behavior or are not fast enough to capture stimuli-responsive phenomena. Here, the authors use X-rays resonant with molecular bonds to demonstrate an in-situ nanoprobe that eliminates the need for labels and enables data collection times within seconds.

    • Terry McAfee
    • , Thomas Ferron
    •  & Brian A. Collins
  • Article
    | Open Access

    While rheology studies have contributed to the understanding of the viscoelastic properties of living cells, the use of higher frequencies promises elucidate the link between cellular and molecular properties. Here authors introduce a rheological assay that measures the cell mechanical response across a continuous frequency range ≈ 1 – 40 kHz.

    • Gotthold Fläschner
    • , Cosmin I. Roman
    •  & Daniel J. Müller
  • Article
    | Open Access

    The competition between the formation of different phases and their kinetics need to be clearly understood to make materials with on-demand and multifaceted properties. Here, the authors reveal, by a combination of complementary in situ techniques, the mechanism of a Cu-Zr-Al metallic glass’s high propensity for metastable phase formation, which is partially through a kinetic mechanism of Al partitioning.

    • Jiri Orava
    • , Shanoob Balachandran
    •  & Ivan Kaban
  • Article
    | Open Access

    A recent report on electrostatic field effect in superconducting devices provides a high potential for advanced quantum technology, but it remains controversial. Here, the authors report that the suppression of critical current, which was attributed to the field effect, can instead be explained by quasiparticle excitations in the constriction of superconducting devices.

    • I. Golokolenov
    • , A. Guthrie
    •  & V. Tsepelin
  • Article
    | Open Access

    Intrinsic mechanical properties of sub-100 nm thin films are markedly difficult to obtain, yet an ever-growing necessity for emerging fields such as soft organic electronics. Here, the authors present a shear motion assisted transfer technique for fabricating free-standing sub-100 nm thin films and measuring their inherent structural–mechanical properties.

    • Luke A. Galuska
    • , Eric S. Muckley
    •  & Xiaodan Gu
  • Article
    | Open Access

    Van der Waals (vdW) magnets have allowed researchers to explore the two dimensional limit of magnetisation; however experimental challenges have hindered analysis of magnetic domains. Here, using an NV centre based probe, the authors analyse the nature of magnetic domains in the vdW magnet, CrBr3.

    • Qi-Chao Sun
    • , Tiancheng Song
    •  & Jörg Wrachtrup
  • Article
    | Open Access

    Polarimetry provides information about physical characteristics of cometary dust. Here, the authors show that the polarization of interstellar comet 2I/Borisov exceeds the typical values for comets, and this together with its polarimetrically homogenous coma suggests a more pristine nature of the object.

    • S. Bagnulo
    • , A. Cellino
    •  & M. Devogèle
  • Article
    | Open Access

    Low secretion rates and evaporation pose challenges for collecting resting thermoregulatory sweat for non-invasive analysis of body physiology. Here the authors present wearable microfluidics-based patches for continuous sweat monitoring at rest that enable detection of pH, Cl, and levodopa for dynamic sweat analysis related to routine activities, stress events, hypoglycemia-induced sweating, and Parkinson’s disease.

    • Hnin Yin Yin Nyein
    • , Mallika Bariya
    •  & Ali Javey
  • Article
    | Open Access

    Electrical nano-sensors hold promise for biofluid interrogation, but their performance is still below the state of the art. Here, self-powered monolayer graphene microelectrodes are shown to enable real-time interrogation of whole-blood flows with 6-month stability and sub-micron/second resolution.

    • Xiaoyu Zhang
    • , Eric Chia
    •  & Jinglei Ping
  • Article
    | Open Access

    The electrical conductivity is critical to understand warm dense matter, but the accurate measurement is extremely challenging. Here the authors use multi-cycle THz pulses to measure the conductivity of gold foils strongly heated by free-electron laser, determining the individual contributions of electron-electron and electron-ion scattering.

    • Z. Chen
    • , C. B. Curry
    •  & S. H. Glenzer
  • Article
    | Open Access

    The obtention and study of actinide elements is challenging due to various factors including their radioactivity and scarcity. Herein, the authors characterize the atomic and electronic structure of Am, Cm, Bk, and Cf compounds using a transmission electron microscopy-based workflow that only requires nanogram amounts of the actinide element.

    • Alexander Müller
    • , Gauthier J.-P. Deblonde
    •  & Andrew M. Minor
  • Article
    | Open Access

    Measuring real time magnetization dynamics resulting from Hall effects is hard due to the small signal size. Here Sala et al demonstrate a method of performing Hall resistance measurements with sub-ns resolution, and use it to investigate the switching of GdFeCo dots induced by spin-orbit torques.

    • G. Sala
    • , V. Krizakova
    •  & P. Gambardella
  • Article
    | Open Access

    The charging of Fe and Mn oxide anodes in lithium-ion batteries are believed to form rocksalt phases via reconstructive conversion reactions. Here, the authors show that MxOy (M = Fe, Mn) transform into non-native body-centred cubic FeO and zincblende MnO via topotactic displacement-like pathways.

    • Xiao Hua
    • , Phoebe K. Allan
    •  & Andrew L. Goodwin
  • Article
    | Open Access

    Magnetic reconnection and plasma turbulence occur in atmospheric and magnetized laboratory plasmas. Here the authors report evolution of magnetic islands and plasma turbulence in tokamak plasmas using high resolution 2D electron cyclotron emission diagnostics.

    • Minjun J. Choi
    • , Lāszlo Bardōczi
    •  & George McKee
  • Article
    | Open Access

    Ferroelectric domain wall profiles can be modeled by phenomenological Ginzburg-Landau theory, with different candidate models and parameters. Here, the authors solve the problem of model selection by developing a Bayesian inference framework allowing for uncertainty quantification and apply it to atomically resolved images of walls. This analysis can also predict the level of microscope performance needed to detect specific physical phenomena.

    • Christopher T. Nelson
    • , Rama K. Vasudevan
    •  & Sergei V. Kalinin
  • Article
    | Open Access

    Single-cell immunoblotting previously separated proteins on a polyacrylamide slab in the xy direction and was limited by throughput and sample consumption. Here the authors adapt the system to separate proteins in the z direction, allowing for closer spacing of sample wells and improved sample consumption.

    • Samantha M. Grist
    • , Andoni P. Mourdoukoutas
    •  & Amy E. Herr
  • Article
    | Open Access

    Controlled particle acceleration in plasmas requires precise measurements of the excited wakefield. Here the authors report and demonstrate a high-resolution method to measure the effective longitudinal electric field of a beam-driven plasma-wakefield accelerator.

    • S. Schröder
    • , C. A. Lindstrøm
    •  & J. Osterhoff
  • Article
    | Open Access

    Optical atomic clocks are useful tools for frequency metrology. Here the authors explore the stability of the atomic clocks and the role of the spin squeezed states for the noise reduction in these clocks.

    • Marius Schulte
    • , Christian Lisdat
    •  & Klemens Hammerer
  • Article
    | Open Access

    Machine learning driven research holds big promise towards accelerating materials’ discovery. Here the authors demonstrate CAMEO, which integrates active learning Bayesian optimization with practical experiments execution, for the discovery of new phase- change materials using X-ray diffraction experiments.

    • A. Gilad Kusne
    • , Heshan Yu
    •  & Ichiro Takeuchi
  • Article
    | Open Access

    Shark teeth have short lifespans yet can be subject to significant mechanical damage. Here, the authors report on a site-specific damage mechanism in shark teeth enameloid, which maintains tooth functional shape, providing experimental evidence that tooth architecture may have influenced the diversification of shark ecologies over evolution.

    • Shahrouz Amini
    • , Hajar Razi
    •  & Peter Fratzl
  • Article
    | Open Access

    Study of structural inhomogeneities in zeolites is important but limited by conventional techniques. Here the authors employ in situ free-electron-laser-based time-resolved coherent X-ray diffraction imaging to visualize the effect of these inhomogeneities during catalytic deoxygenation of NOx.

    • Jinback Kang
    • , Jerome Carnis
    •  & Hyunjung Kim
  • Perspective
    | Open Access

    Discovering a sustainable route to ammonia as a fertiliser and as an energy carrier is critically important, but many recent reports on the electrochemical nitrogen reduction are false positives. Here the authors uncover the emerging experimental traps and detail protocols to reliably avoid them.

    • Jaecheol Choi
    • , Bryan H. R. Suryanto
    •  & Alexandr N. Simonov
  • Article
    | Open Access

    Additive manufacturing promises a major transformation of the production of high economic value metallic materials. Here, the authors describe a new class of 3D printable superalloys that are amenable to crack-free 3D printing via electron beam melting as well as selective laser melting.

    • Sean P. Murray
    • , Kira M. Pusch
    •  & Tresa M. Pollock