Magnetic and superconducting ordering in one-dimensional nanostructures at the LaAlO3/SrTiO3 interface

We formulate a model for magnetic and superconducting ordering in one-dimensional nanostructures at LaAlO3/SrTiO3 interfaces containing both localized magnetic moments and itinerant electrons. Although these both originate in Ti 3d orbitals, the former may be due to electrons more tightly bound to the interface, while the latter are extended over several layers. Only the latter contribute significantly to metallic conduction and superconductivity. In our model, the interplay between the two types of electrons, which is argued to be ferromagnetic, combined with strong spin-orbit coupling of the itinerant electrons, leads to magnetic ordering. Furthermore, we propose a model for interfacial superconductivity, consisting of random superconducting grains in the bulk SrTiO3 driven, via coupling to the interface conduction band, towards long-ranged or quasi-long-ranged order. Most interestingly, the magnetic order and strong spin-orbit coupling can lead in this manner to unconventional interfacial superconductivity, yielding a possible realization of Majorana physics. DOI: 10.1103/PhysRevB.87.014436