The rings, which can be positiond on metal electrodes, to allow study of novel electric transport phenomena. Shown is an AFM micrograph of a one micron-diameter ring (the purple circle) placed over gold electrodes (the light blue objects).

The nanotubes used to form the rings are extremely small; their diameter is only 1.4 nm. They are 1-dimensional conductors and at low temperatures, quantum interference phenomena dominate electrical transport through the tubes. The ring geometry allows observation of such quantum effects in these 1D conductors. There is clear evidence of weak localization, which enables determination of the electron's phase coherence length, which can be as large as 0.5 mm at 3 K.