Events

Title: "Advances in multiscale simulations of superconducting devices"

While modern experimental techniques are enabling increasingly multifold studies of superconductivity (from in-situ synthesis to transport and scanning-probe measurements), the community has witnessed an increasing gap between the ab initio calculations and those on mean-field levels, and even more to the desired device modelling. At present, the only tool able to address the needed multi-scale modelling of superconductors, nanopatterned into electronic circuitry, are the advanced Ginzburg-Landau simulations. We have recently developed a multiscale approach where first information about fermiology, vibrational modes, and electron-phonon coupling are obtained from first principles for the materials of interest [1], to be subsequently translated into (anisotropic) superconducting properties, that can further serve to properly parametrize mean-field models to capture the behavior of that superconductor in applied magnetic field and electric current.

In this talk, I will review our recent further breakthroughs in that respects, and show realized numerical experimentation on circuits of arbitrary shape (on advanced size and time scale), variable thickness, inhomogeneous parameters, with self-consistent account for magnetic field distribution, the electric field generated under applied current, incorporated heating effects, thus fully characterized behavior of the superconducting condensate in non-equilibrium conditions that reveals physics behind improved or worsened performance of various realistic transport devices [2-4].

References

[1] J. Bekaert et al., Phys. Rev. B 94, 144506 (2016); Phys. Rev. B 96, 094510 (2017).

[2] L. Embon et al., Nature Commun. 8, 85 (2017).

[3] J. Lombardo et al., Nanoscale 10, 1987 (2018).

[4] R. Cordoba et al., in preparation.

Prof Fernando Castro, Head of Materials Science & Engineering at the National Physical Laboratory, UK.

Title: "Multiscale characterisation for nanoelectronics"

This talk will provide a brief introduction to Materials Metrology at NPL and then focus on examples of multiscale characterisation for nanoelectronics. Novel optoelectronic devices make use of advanced nanomaterial systems, where the nanoscale composition and morphology significantly affects the performance. Despite advances in analytical characterisation methods, such structure-property relationship is very challenging to measure directly.

NPL has been developing a suite of characterisation techniques to measure these materials and devices in situ and with high spatial resolution.

We will cover examples where these methods are applied to solar cells, 2D materials and nanowire based electronics, from macroscopic measurements down to the nanoscale.