Geometric dependence of Nb-Bi2{_2}Te3{_3}-Nb topological Josephson junction transport parameters

Superconductor-topological insulator-superconductor Josephson junctions have been fabricated in order to study the width dependence of the critical current, normal state resistance and flux periodicity of the critical current modulation in an external field. Previous literature reports suggest anomalous scaling in topological junctions due to the presence of Majorana bound states. However, for most realised devices, one would expect that trivial $2\pi$-periodic Andreev levels dominate transport. We also observe anomalous scaling behaviour of junction parameters, but the scaling can be well explained by mere geometric effects, such as the parallel bulk conductivity shunt and flux focusing

Volunteers in Health Care. Visions, Ambitions and Aspirations of different Age Groups.

Steeds meer mensen hebben zorg nodig, waarbij ze voor een groot deel aangewezen zijn op de beschikbaarheid van vrijwilligers (en mantelzorgers). De voornaamste bedreiging die zich voordoet, is de afname van het aantal vrijwilligers vanwege de vergrijzing en de eenzijdige samenstelling van het vrijwilligersbestand van ouderen (boven de 55 jaar). De groep jongere vrijwilligers in de leeftijd van 28 tot 43 jaar is ondervertegenwoordigd. Er bestaat wel degelijk behoefte om 'meer' te doen, maar het blijkt dat de inpassing binnen de huidige werkwijze niet aansluit op de leefstijl en ambities van jongere vrijwilligers. Het doel van dit onderzoek is te achterhalen waarom de inpassing van de jongere generatie vrijwilligers in de zorg soms moeizaam verloopt binnen het huidige vrijwilligerswerk

Effect of high oxygen pressure annealing on superconducting Nd1.85Ce0.15CuO4 thin films by pulsed laser deposition from Cu-enriched targets

We show that the quality of Nd1.85Ce0.15CuO4 films grown by pulsed laser deposition can be enhanced by using a non-stoichiometric target with extra copper added to suppress the formation of a parasitic (Nd, Ce)2O3 phase. The properties of these films are less dependent on the exact annealing procedure after deposition as compared to films grown from a stoichiometric target. Film growth can be followed by a 1 bar oxygen annealing, after an initial vacuum annealing, while retaining the superconducting properties and quality. This enables the integration of electron-doped cuprates with their hole-doped counterparts on a single chip, to create, for example, superconducting pn-junctions.Comment: This is an author-created, un-copyedited version of an article accepted for publication in Superconductor Science and Technology. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0953-2048/27/4/04401

Magnetoresistance from time-reversal symmetry breaking in topological materials

Magnetotransport measurements are a popular way of characterizing the electronic structure of topological materials and often the resulting datasets cannot be described by the well-known Drude model due to large, non-parabolic contributions. In this work, we focus on the effects of magnetic fields on topological materials through a Zeeman term included in the model Hamiltonian. To this end, we re-evaluate the simplifications made in the derivations of the Drude model and pinpoint the scattering time and Fermi velocity as Zeeman-term dependent factors in the conductivity tensor. The driving mechanisms here are the aligment of spins along the magnetic field direction, which allows for backscattering, and a significant change to the Fermi velocity by the opening of a hybridization gap. After considering 2D and 3D Dirac states, as well as 2D Rashba surface states and the quasi-2D bulk states of 3D topological insulators, we find that the 2D Dirac states on the surfaces of 3D topological insulators produce magnetoresistance, that is significant enough to be noticable in experiments. As this magnetoresistance effect is strongly dependent on the spin-orbit energy, it can be used as a telltale sign of a Fermi energy located close to the Dirac point