Multiphase superconductivity in PdBi.

Unconventional superconductivity, where electron pairing does not involve electron-phonon interactions, is often attributed to magnetic correlations in a material. Well known examples include high-T cuprates and uranium-based heavy fermion superconductors. Less explored are unconventional superconductors with strong spin-orbit coupling, where interactions between spin-polarised electrons and external magnetic field can result in multiple superconducting phases and field-induced transitions between them, a rare phenomenon in the superconducting state.

The quantum twisting microscope.

The invention of scanning probe microscopy revolutionized the way electronic phenomena are visualized. Whereas present-day probes can access a variety of electronic properties at a single location in space, a scanning microscope that can directly probe the quantum mechanical existence of an electron at several locations would provide direct access to key quantum properties of electronic systems, so far unreachable. Here, we demonstrate a conceptually new type of scanning probe microscope-the quantum twisting microscope (QTM)-capable of performing local interference experiments at its tip.

How Electron Hydrodynamics Can Eliminate the Landauer-Sharvin Resistance.

It has long been realized that even a perfectly clean electronic system harbors a Landauer-Sharvin resistance, inversely proportional to the number of its conduction channels. This resistance is usually associated with voltage drops on the system's contacts to an external circuit. Recent theories have shown that hydrodynamic effects can reduce this resistance, raising the question of the lower bound of resistance of hydrodynamic electrons.

Imaging hydrodynamic electrons flowing without Landauer-Sharvin resistance.

Electrical resistance usually originates from lattice imperfections. However, even a perfect lattice has a fundamental resistance limit, given by the Landauer conductance caused by a finite number of propagating electron modes. This resistance, shown by Sharvin to appear at the contacts of electronic devices, sets the ultimate conduction limit of non-interacting electrons.

Enhanced Superconductivity in Few-Layer TaS due to Healing by Oxygenation.

When approaching the atomically thin limit, defects and disorder play an increasingly important role in the properties of two-dimensional (2D) materials. While defects are generally thought to negatively affect superconductivity in 2D materials, here we demonstrate the contrary in the case of oxygenation of ultrathin tantalum disulfide (TaS). Our first-principles calculations show that incorporation of oxygen into the TaS crystal lattice is energetically favorable and effectively heals sulfur vacancies typically present in these crystals, thus restoring the electronic band structure and the carrier density to the intrinsic characteristics of TaS.

Composite super-moiré lattices in double-aligned graphene heterostructures.

When two-dimensional (2D) atomic crystals are brought into close proximity to form a van der Waals heterostructure, neighbouring crystals may influence each other's properties. Of particular interest is when the two crystals closely match and a moiré pattern forms, resulting in modified electronic and excitonic spectra, crystal reconstruction, and more. Thus, moiré patterns are a viable tool for controlling the properties of 2D materials.

Visualizing Poiseuille flow of hydrodynamic electrons.

Hydrodynamics, which generally describes the flow of a fluid, is expected to hold even for fundamental particles such as electrons when inter-particle interactions dominate. Although various aspects of electron hydrodynamics have been revealed in recent experiments, the fundamental spatial structure of hydrodynamic electrons-the Poiseuille flow profile-has remained elusive. Here we provide direct imaging of the Poiseuille flow of an electronic fluid, as well as a visualization of its evolution from ballistic flow.

Publisher Correction: Imaging work and dissipation in the quantum Hall state in graphene.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Imaging work and dissipation in the quantum Hall state in graphene.

Topology is a powerful recent concept asserting that quantum states could be globally protected against local perturbations. Dissipationless topologically protected states are therefore of major fundamental interest as well as of practical importance in metrology and quantum information technology. Although topological protection can be robust theoretically, in realistic devices it is often susceptible to various dissipative mechanisms, which are difficult to study directly because of their microscopic origins.

Strong magnetophonon oscillations in extra-large graphene.

Van der Waals materials and their heterostructures offer a versatile platform for studying a variety of quantum transport phenomena due to their unique crystalline properties and the exceptional ability in tuning their electronic spectrum. However, most experiments are limited to devices that have lateral dimensions of only a few micrometres. Here, we perform magnetotransport measurements on graphene/hexagonal boron-nitride Hall bars and show that wider devices reveal additional quantum effects.

Simultaneous voltage and current density imaging of flowing electrons in two dimensions.

A variety of physical phenomena associated with nanoscale electron transport often results in non-trivial spatial voltage and current patterns, particularly in nonlocal transport regimes. While numerous techniques have been devised to image electron flows, the need remains for a nanoscale probe capable of simultaneously imaging current and voltage distributions with high sensitivity and minimal invasiveness, in a magnetic field, across a broad range of temperatures and beneath an insulating surface. Here we present a technique for spatially mapping electron flows based on a nanotube single-electron transistor, which achieves high sensitivity for both voltage and current imaging.

Unusual Suppression of the Superconducting Energy Gap and Critical Temperature in Atomically Thin NbSe.

It is well-known that superconductivity in thin films is generally suppressed with decreasing thickness. This suppression is normally governed by either disorder-induced localization of Cooper pairs, weakening of Coulomb screening, or generation and unbinding of vortex-antivortex pairs as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory. Defying general expectations, few-layer NbSe, an archetypal example of ultrathin superconductors, has been found to remain superconducting down to monolayer thickness.

Imaging resonant dissipation from individual atomic defects in graphene.

Conversion of electric current into heat involves microscopic processes that operate on nanometer length scales and release minute amounts of power. Although central to our understanding of the electrical properties of materials, individual mediators of energy dissipation have so far eluded direct observation. Using scanning nanothermometry with submicrokelvin sensitivity, we visualized and controlled phonon emission from individual atomic-scale defects in graphene.

Edge currents shunt the insulating bulk in gapped graphene.

An energy gap can be opened in the spectrum of graphene reaching values as large as 0.2 eV in the case of bilayers. However, such gaps rarely lead to the highly insulating state expected at low temperatures.

Nacre-nanomimetics: Strong, Stiff, and Plastic.

The bricks and mortar in the classic structure of nacre have characteristic geometry, aspect ratios and relative proportions; these key parameters can be retained while scaling down the absolute length scale by more than 1 order of magnitude. The results shed light on fundamental scaling behavior and provide new opportunities for high performance, yet ductile, lightweight nanocomposites. Reproducing the toughening mechanisms of nacre at smaller length scales allows a greater volume of interface per unit volume while simultaneously increasing the intrinsic properties of the inorganic constituents.

Characterization by NMR of reactants and products of hydrofluoroether isomers, CF3(CF2)3OCH3 and (CF3)2C(F)CF2OCH3, reacting with isopropyl alcohol.

The 3M Company product Novec™ 71IPA DL, a mixture of methoxyperfluorobutane, methoxyperfluoroisobutane and 4.5 wt.% isopropyl alcohol, has been found to be very stable at ambient temperature, producing fluoride at the rate of ~1 ppm/year.

Leiomyosarcoma of the inferior vena cava: a case report and review of the literature.

A 68-year-old white female presented with two years of progressively worsening dyspnea. Echocardiography revealed a large right atrial mass and partial obstruction of the inferior vena cava. Further imaging revealed a cystic dense mass in the inferior vena cava and right atrium.

P-wave morphology correlation with left atrial volumes assessed by 2-dimensional echocardiography.

To correlate prespecified P-wave morphologies with echocardiographically derived left atrial volumes (LAVs), we studied a convenience sample of 71 patients with predominantly normal left ventricular systolic function (mean ejection fraction = 58.2% +/- 6.6%) who underwent concurrent 2-dimensional echocardiogram and 12-lead electrocardiogram.

Hemolytic anemia produced by regurgitation through transposed chordae tendineae.

Hemolytic anemia after mitral repair and annuloplasty ring placement is very uncommon, and rarely described. The case is presented of a 53-year-old woman who developed severe mitral regurgitation and transfusion-dependent hemolytic anemia following mitral valve repair with a Carpentier-Edwards annuloplasty ring, which included transposition of chordae tendineae from the posterior leaflet to the anterior leaflet. Transesophageal echocardiography suggested that the transposed chordae tethered the anterior leaflet, causing malcoaptation of the leaflets.

Surface structure of human mucin using X-ray photoelectron spectroscopy.

X-ray photoelectron spectroscopy (XPS) is a surface sensitive analytical technique that measures the binding energy of electrons in atoms and molecules on the surface of a material. XPS was used to determine the distribution of the oligosaccharide side chains in the glycoprotein, MUC1 mucin. Low-resolution XPS spectra provided elemental composition of MUC1 mucin (fully glycosylated), mucin polypeptide (nonglycosylated), and carbohydrates found in mucin.

Health care costs of obesity in New Zealand.

Objective: To estimate the costs of health care that are attributable to obesity in New Zealand.

Methods: The 1991 health care costs of non-insulin dependent diabetes, coronary heart disease, hypertension, gallstone disease, post-menopausal breast cancer and colon cancer were estimated and multiplied by the population attributable factor for obesity for each condition. The relative risk estimates were taken from the literature, the obesity prevalence from a 1990 New Zealand survey, and the costs and volumes of services were taken from a variety of sources and covered hospital (inpatient and outpatient) services, general practitioner consultations, pharmaceuticals, laboratory tests and ambulance services.

Weaning; a position statement.

1. Weaning is the process by which the milk fed infant is gradually accustomed to a varied diet. 2.