The Kondo effect in a single-electron transistor

Abstract

The Kondo effect, which occurs when a metal with magnetic impurities is cooled to low temperatures, has been a focus of research in solid-state physics for several decades. I have designed, fabricated, and measured a system which behaves as a single "artificial" impurity in a metal, displaying the Kondo effect. This so-called Single-Electron Transistor (SET) has several advantages over the classic bulk Kondo systems. Most obviously, only one impurity is involved, so there is no need to worry about interactions between impurities, or different impurities feeling different environments. But even more importantly all the parameters of the system, such as the binding energy of electrons on the impurity and the tunneling rate between metal and impurity, can be tuned in-situ, allowing detailed quantitative comparison to thirty years of theoretical developments whose details could not be tested in previously-studied Kondo systems.