Magnetic field resistant quantum interferences in bismuth nanowires based Josephson junctions

We investigate proximity induced superconductivity in micrometer-long bismuth nanowires con- nected to superconducting electrodes with a high critical field. At low temperature we measure a supercurrent that persists in magnetic fields as high as the critical field of the electrodes (above 11 T). The critical current is also strongly modulated by the magnetic field. In certain samples we find regular, rapid SQUID-like periodic oscillations occurring up to high fields. Other samples ex- hibit less periodic but full modulations of the critical current on Tesla field scales, with field-caused extinctions of the supercurrent. These findings indicate the existence of low dimensionally, phase coherent, interfering conducting regions through the samples, with a subtle interplay between orbital and spin contributions. We relate these surprising results to the electronic properties of the surface states of bismuth, strong Rashba spin-orbit coupling, large effective g factors, and their effect on the induced superconducting correlations.Comment: 5 page

Supercapacitor and supercapattery as emerging electrochemical energy stores

This article reviews critically selected recent literature on electrochemical energy storage (EES) technologies, focusing on supercapacitor and also supercapattery which is a generic term for various hybrid devices combining the merits of rechargeable battery and supercapacitor. Fundamentals of EES are explained, aiming at clarification of some literature confusions such as the differences between capacitive and non-capacitive Faradaic charge storage mechanisms, and between cathode and positive electrode (positrode), and between anode and negative electrode (negatrode). In particular, the concept and origin of pseudocapacitance are qualitatively correlated with the band model for semiconductors. Strategies for design and construction of supercapattery are discussed in terms of both the materials structures and device engineering. Selection of materials, including electrolytes, is another topic reviewed selectively. Graphenes and carbon nanotubes are the favourable choice to composite with both capacitive and non-capacitive redox materials for improved kinetics of charge storage processes and charge-discharge cycling stability. Organoaqueous electrolytes show a great potential to enable EES to work at sub-zero temperatures, whilst solid ion conducting membranes and ionic liquids can help develop high voltage (> 4.0 V) and hence high energy supercapatteries

'Hydrogen storage' under oxidative conditions: a pandemic case

International audienceThis Opinion attracts attention to an evident problem with interpretation of some data for oxides and oxide-based compositions in aqueous alkaline medium in terms of 'hydrogen storage'. The potentials corresponding to both 'charge' and 'discharge', as reported in numerous recently published works, exceed oxygen equilibrium potential. Under these highly oxidative conditions, the risk of by-side processes is high enough. The reported record values of 'discharge capacity' can be hardly agreed with any possible type of hydrogen bonding in oxide lattice

The Bottleneck for Precise Electrochemical Characterization of PdHx: Slow α↔β Phase Transition

International audienc