Spring 2005 Physics Colloquium
February 18; Friday, PAS 220, 3pm
Marc Kastner
MIT
The Kondo Effect in Single-Electron Transistors and Other Nanostructures
Lithographic techniques, developed for the electronics industry, allow us
to make an unusual kind of device, the Single-Electron Transistor
(SET). The SET consists of a region of semiconductor, in which the
electrons are confined, coupled to electrical leads through tunnel
junctions. When the tunneling is very weak, the electrons are strongly
confined, and the transistor turns on and off again for every electron
added to it, hence its name. However, when the tunneling is strong, the
electron's wave function is both inside and outside the transistor, at the
same time. This causes the Kondo effect. In this talk, I will explain how
we make SET's and why they behave as they do. I will then show how we
identify the Kondo effect and how we understand it. Finally, I will show
that our results are very similar to those seen in transistors made of
single molecules by other groups.