Sub-kelvin Andreev reflection spectroscopy of superconducting gaps in FeSe

Andreev-reflection and Point-contact Spectroscopy of Superconducting Rare Earth Transition Metal Borocarbides

Superconducting gap structure of FeSe

The microscopic mechanism governing the zero-resistance flow of current in some iron-based, high-temperature superconducting materials is not well understood up to now. A central issue concerning the investigation of these materials is their superconducting gap symmetry and structure. Here we present a combined study of low-temperature specific heat and scanning tunnelling microscopy measuremen...

Photoassociation Spectroscopy in Penning Ionization Reactions at Sub-Kelvin Temperatures.

Penning ionization reactions in merged beams with precisely controlled collision energies have been shown to accurately probe quantum mechanical effects in reactive collisions. A complete microscopic understanding of the reaction is, however, faced with two major challenges-the highly excited character of the reaction's entrance channel and the limited precision of even the best state-of-the-ar...

Andreev reflection in graphene nanoribbons

We study Andreev reflection in graphene nanoribbon/superconductor hybrid junctions. By using a tightbinding approach and the scattering formalism we show that finite-size effects lead to notable differences with respect to the bulk-graphene case. At subgap voltages, conservation of pseudoparity, a quantum number characterizing the ribbon states, yields either a suppression of Andreev reflection...

Specular Andreev reflection in graphene.

By combining the Dirac equation of relativistic quantum mechanics with the Bogoliubov-de Gennes equation of superconductivity we investigate the electron-hole conversion at a normal-metal-superconductor interface in graphene. We find that the Andreev reflection of Dirac fermions has several unusual features: (1) the electron and hole occupy different valleys of the band structure; (2) at normal...