Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 3: Focus Session: Spins on Surfaces studied by Atomic Scale Spectroscopies I
O 3.4: Talk
Monday, March 18, 2024, 11:30–11:45, MA 004
Electron transport in magnetic atomic and molecular junctions between superconducting leads — •Nicolas Lorente1,2,3, Divya Jyoti2,3, Cristina Mier2,3, and Deung-Jang Choi2,3 — 1Centro de Física de Materiales (CSIC-EHU), San Sebastian, Spain — 2Materials Physics Center, San Sebastian, Spain — 3Donostia International Physics Center, San Sebastian, Spain
We present experiments and theory using self-consistent Bogoliubov-de Gennes equations implemented with Green's function for wide-band s-wave superconductors. We show the effect of magnetic junctions and multiple Andreev reflection when there are localized magnetic moments in the junction. The theoretical results agree with experiments performed on Nickelocene molecules trapped between a superconducting tip and a superconducting surface. Adding Fe atoms to the junctions enhances the magnetic scattering which can be easily modeled with the theory. Experimentally, the Fe atoms can be manipulated to be between molecule and interface or to be subsurface, with very different signature in the differential conductance. Self-consistency does not alter the results except when studying the evolution of the order parameter, which has bearings in the prediction of normal and topological quantum phase transitions.
Keywords: Multiple Andreev Reflection; Self-consistent Bogoliubov de Gennes; Magnetic atomic and molecular junctions; scanning tunneling microscope; superconducting electrodes