Magneto-transport Study on the nanometer-scaled quantum-ring interferometer made of Al$_{x}$Ga$_{1-x}$N/GaN heterostructures*

The quantum-ring interferometer has been proposed for spintronic application. The Al$_{x}$Ga$_{1-x}$N/GaN samples were grown on GaN-template buffer layer by plasma-assisted molecular beam epitaxy. We obtained the mobility and carrier density of two-dimensional electron gas to be 19845 cm$^{2}$/Vs and 5.18x10$^{12}$ cm$^{-2}$ by conventional van der pauw Hall measurement at temperature of 4.2 K, respectively. The samples were used to fabricate quantum-ring field-effect-transistors with different widths of conducting channel by Focus Ion Beam. The magneto-resistance measurement at temperature of 0.35 K and magnetic field up to 12 T was performed on these samples. The electronic characterization of nanometer-scaled quantum-ring made of high-mobility Al$_{x}$Ga$_{1-x}$N/GaN heterostructures has been studied.