Tunable Generation of Correlated Vortices in Open Superconductor Tubes

As shown theoretically, geometry determines the dynamics of vortices in the presence of transport currents in open superconductor micro- and nanotubes subject to a magnetic field orthogonal to the axis. In low magnetic fields, vortices nucleate periodically at one edge of the tube, subsequently move along the tube under the action of the Lorentz force and denucleate at the opposite edge of the tube. In high magnetic fields, vortices pass along rows closest to the slit. Intervortex correlations lead to an attraction between vortices moving at opposite sides of a tube. Open superconductor nanotubes provide a tunable generator of superconducting vortices for fluxon-based quantum computing

Tunable Generation of Correlated Vortices in Open Superconductor Tubes

As shown theoretically, geometry determines the dynamics of vortices in the presence of transport currents in open superconductor micro- and nanotubes subject to a magnetic field orthogonal to the axis. In low magnetic fields, vortices nucleate periodically at one edge of the tube, subsequently move along the tube under the action of the Lorentz force and denucleate at the opposite edge of the tube. In high magnetic fields, vortices pass along rows closest to the slit. Intervortex correlations lead to an attraction between vortices moving at opposite sides of a tube. Open superconductor nanotubes provide a tunable generator of superconducting vortices for fluxon-based quantum computing

Tunable Generation of Correlated Vortices in Open Superconductor Tubes

As shown theoretically, geometry determines the dynamics of vortices in the presence of transport currents in open superconductor micro- and nanotubes subject to a magnetic field orthogonal to the axis. In low magnetic fields, vortices nucleate periodically at one edge of the tube, subsequently move along the tube under the action of the Lorentz force and denucleate at the opposite edge of the tube. In high magnetic fields, vortices pass along rows closest to the slit. Intervortex correlations lead to an attraction between vortices moving at opposite sides of a tube. Open superconductor nanotubes provide a tunable generator of superconducting vortices for fluxon-based quantum computing

Tunable Generation of Correlated Vortices in Open Superconductor Tubes

As shown theoretically, geometry determines the dynamics of vortices in the presence of transport currents in open superconductor micro- and nanotubes subject to a magnetic field orthogonal to the axis. In low magnetic fields, vortices nucleate periodically at one edge of the tube, subsequently move along the tube under the action of the Lorentz force and denucleate at the opposite edge of the tube. In high magnetic fields, vortices pass along rows closest to the slit. Intervortex correlations lead to an attraction between vortices moving at opposite sides of a tube. Open superconductor nanotubes provide a tunable generator of superconducting vortices for fluxon-based quantum computing

Self-Propelled Micromotors for Cleaning Polluted Water

We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water <i>via</i> the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, <i>i</i>.<i>e</i>., the inner Pt for the self-propulsion and the outer Fe for the <i>in situ</i> generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants <i>ca.</i> 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction–diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water

Self-Propelled Micromotors for Cleaning Polluted Water

We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water <i>via</i> the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, <i>i</i>.<i>e</i>., the inner Pt for the self-propulsion and the outer Fe for the <i>in situ</i> generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants <i>ca.</i> 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction–diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water

Self-Propelled Micromotors for Cleaning Polluted Water

We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water <i>via</i> the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, <i>i</i>.<i>e</i>., the inner Pt for the self-propulsion and the outer Fe for the <i>in situ</i> generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants <i>ca.</i> 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction–diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water

Electrical Properties of Hybrid Nanomembrane/Nanoparticle Heterojunctions: The Role of Inhomogeneous Arrays

Investigation of charge transport mechanisms across inhomogeneous nanoparticle (NP) layers in heterojunctions is one of the key technological challenges nowadays for developing novel hybrid nanostructured functional elements. Here, we successfully demonstrate for the first time the fabrication and characterization of a novel hybrid organic/inorganic heterojunction, which combines free-standing metallic nanomembranes with self-assembled mono- and sub-bilayers of commercially available colloidal NPs with no more than ∼10⁵ NPs. The low-temperature conductance–voltage spectra exhibit Coulomb features that correlate with various interface’s configurations, including the presence of inhomogeneities at the nano- and micrometer scale owing to the NP size, the micrometer-sized voids, and the thickness of the layers. The charge transport features observed can be explained by a superposition of conductance characteristics of each individual type of NPs. The procedure adopted to fabricate the heterojunctions as well as the theoretical approach employed to study the charge transport mechanisms across the NP layers may be of interest for investigating different types of NPs and commonly obtained inhomogeneous layers. In addition, the combination of metallic nanomembranes with self-assembled layers of NPs makes such a hybrid organic/inorganic heterostructure an interesting platform and building block for future nanoelectronics, especially after intentional tuning of its electronic behavior

In-Plane Thermal Conductivity of Radial and Planar Si/SiO_<i>x</i> Hybrid Nanomembrane Superlattices

Silicon, although widely used in modern electronic devices, has not yet been implemented in thermoelectric applications mainly due to its high thermal conductivity, κ, which leads to an extremely low thermoelectric energy conversion efficiency (figure of merit). Here, we present an approach to manage κ of Si thin-film-based nanoarchitectures through the formation of radial and planar Si/SiO_<i>x</i> hybrid nanomembrane superlattices (HNMSLs). For the radial Si/SiO_<i>x</i> HNMSLs with various numbers of windings (1, 2, and 5 windings), we observe a continuous reduction in κ with increasing number of windings. Meanwhile, the planar Si/SiO_<i>x</i> HNMSL, which is fabricated by mechanically compressing a five-windings rolled-up microtube, shows the smallest in-plane thermal conductivity among all the reported values for Si-based superlattices. A theoretical model proposed within the framework of the Born–von Karman lattice dynamics to quantitatively interpret the experimental data indicates that the thermal conductivity of Si/SiO_<i>x</i> HNMSLs is to a great extent determined by the phonon processes in the SiO_<i>x</i> layers