Researchers from the MAGNETRANS-UAM group, working with collaborators at the University at Buffalo (SUNY, USA) and in University of Loraine, France, have discovered an unusually large shot noise in epitaxial superconducting V/MgO/Fe junctions. The origin of this giant noise is a peculiar realization of a superconducting proximity effect, where a simple superconductor influences its neighbors. The measurements reveal largely unexplored implications of orbital-symmetry-controlled proximity effects. The importance of orbital symmetries and the accompanying spin-orbit coupling is manifested by an unexpected emergence of another superconducting region strikingly different from the parent superconductor. Unlike vanadium’s common spin-singlet superconductivity, the broken inversion symmetry in V/MgO/Fe junctions and the resulting interfacial spin-orbit coupling leads to the formation of spin-triplet superconductivity across the ferromagnetic iron. The authors show that the enhanced shot noise, known from Josephson junctions with two superconductors, could be measured even in a single superconductor. This discovery, recently published in Nature Communications, motivates revisiting how the spin-orbit coupling and superconducting proximity effects can transform many materials. [Full Article]
