0000000000853335

AUTHOR

Alessandro Braggio

0000-0003-2119-1160

showing 3 related works from this author

Signatures of topological phase transitions in Josephson current-phase discontinuities

2016

Topological superconductors differ from topologically trivial ones for the presence of topologically protected zero-energy modes. To date, experimental evidence of topological superconductivity in nanostructures has been mainly obtained by measuring the zero-bias conductance peak via tunneling spectroscopy. Here, we propose an alternative and complementary experimental recipe to detect topological phase transitions in these systems. We show in fact that, for a finite-sized system with broken time-reversal symmetry, discontinuities in the Josephson current-phase relation correspond to the presence of zero-energy modes and to a change in the fermion parity of the groundstate. Such discontinui…

Phase transitionFOS: Physical sciences02 engineering and technologyClassification of discontinuitiesTopology01 natural sciencesSymmetry protected topological orderSuperconductivity (cond-mat.supr-con)Quantum mechanics0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)ElectronicOptical and Magnetic Materials010306 general physicsQuantum tunnellingTopological quantum numberElectronic Optical and Magnetic Materials; Condensed Matter PhysicsSuperconductivityPhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed matter physicsCondensed Matter - SuperconductivityFermionCondensed Matter Physics021001 nanoscience & nanotechnology0210 nano-technologyGround state
researchProduct

Thermodynamics of a Phase-Driven Proximity Josephson Junction

2019

We study the thermodynamic properties of a superconductor/normal metal/superconductor Josephson junction {in the short limit}. Owing to the proximity effect, such a junction constitutes a thermodynamic system where {phase difference}, supercurrent, temperature and entropy are thermodynamical variables connected by equations of state. These allow conceiving quasi-static processes that we characterize in terms of heat and work exchanged. Finally, we combine such processes to construct a Josephson-based Otto and Stirling cycles. We study the related performance in both engine and refrigerator operating mode.

Josephson effectsns junctionStirling enginesuprajohtavuusGeneral Physics and Astronomy02 engineering and technology01 natural sciences7. Clean energysuprajohteetlaw.inventionlawJosephson junctionMaxwell relationCondensed Matter::Superconductivityquasi-particles entropykvanttifysiikkalcsh:Scienceproximity effect; superconductivity; Josephson junction; SNS junction; Josephson thermodynamics; Maxwell relation; quasi-particles entropy; quantum thermodynamics; quantum machines; quantum coolersPhysicsSuperconductivityQuantum PhysicsCondensed matter physicssuperconductivitySupercurrent021001 nanoscience & nanotechnologyThermodynamic systemlcsh:QC1-999termodynamiikkaproximity effectjosephson thermodynamics0210 nano-technologyRefrigerator carFOS: Physical sciencesJosephson thermodynamicslcsh:AstrophysicsArticleSuperconductivity (cond-mat.supr-con)Entropy (classical thermodynamics)quantum coolers0103 physical sciencesMesoscale and Nanoscale Physics (cond-mat.mes-hall)lcsh:QB460-466010306 general physicsquantum machinesPhase differenceCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed Matter - SuperconductivitySNS junctionjosephson junctionmaxwell relationquantum thermodynamicslcsh:QQuantum Physics (quant-ph)lcsh:PhysicsEntropy
researchProduct

Superconducting size effect in thin films under electric field: Mean-field self-consistent model

2019

We consider effects of an externally applied electrostatic field on superconductivity, self-consistently within a BCS mean field model, for a clean 3D metal thin film. The electrostatic change in superconducting condensation energy scales as $\mu^{-1}$ close to subband edges as a function of the Fermi energy $\mu$, and follows 3D scaling $\mu^{-2}$ away from them. We discuss nonlinearities beyond gate effect, and contrast results to recent experiments.

---Josephson effectsuprajohtavuusFOS: Physical sciences02 engineering and technology01 natural sciencessuprajohteetSuperconductivity (cond-mat.supr-con)superconducting phase transitionElectric fieldCondensed Matter::Superconductivity0103 physical sciencesThin film010306 general physicsScalingCondensed Matter::Quantum GasesSuperconductivityPhysicsCondensed matter physicsCondensed Matter - SuperconductivityFermi energy021001 nanoscience & nanotechnologyMean field theorythin filmsmesoscopicsohutkalvot0210 nano-technologyEnergy (signal processing)Physical Review B
researchProduct