Coulomb blockade phenomena in confined LaAlO$_3$/SrTiO$_3$ nanowires

The LaAlO$_3$/SrTiO$_3$ interface hosts a rich variety of phenomena, including gate-tunable conductivity, ferromagnetism, and low-temperature superconductivity. Nanowires at the interface are fabricated with conductive AFM lithography; this flexible process allows complex nanostructures to be created to study the various phenomena at the interface. Here, tunneling barriers are created to confine a section of wire. Low temperature transport through these confined wires is gate-tunable, exhibiting superconductivity in the strong coupling regime and Coulomb blockade in the weak coupling regime. The Coulomb peaks exhibit interesting behavior in an external magnetic field. The peaks are insensitive to low fields; however, they begin to split and shift above a critical magnetic field. The curious splitting of each Coulomb peak above a critical field could provide insight into the fundamental magnetic, superconducting, and spin-orbit properties at the interface.