Wikipedia
The quiteron is a superconducting three-terminal, three layer switching device similar to transistor. It was proposed by Sadeg Faris, then working for IBM, in 1982, and is distinct from superconductive Josephson junction. Quiteron's characteristics are very low switching energy requirements and extremely fast switching times on the order of 10 s. It works on principles of quantum tunneling by injecting quasiparticles through the two thin insulator layers separating the three superconducting layers. Quiteron has yet found no significant practical use as of 2009.
The original quiteron consisted of three superconducting layers. Two layers were made of niobium, the third of lead-indium-gold alloy. They were insulated with silicon monoxide and niobium oxide layers.