Kondo Physics Seen in a Quantum Dot

JAN 01, 1998

More than 30 years after the discovery of the Kondo effect, which is caused by magnetic impurities in metals, researchers may now be able to study the phenomenon more precisely because a quantum dot with an odd number of electrons seems to mimic the behavior of an individual magnetic atom.

DOI: 10.1063/1.882089

Barbara Goss Levi

A quantum dot, as its name implies, is a minuscule region of metallic or semiconductor material whose dimensions can be as small as a few tens of nanometers on a side. It has been likened to an artificial atom because it carries a discrete charge and quantized electronic energy levels (see the article by Marc Kastner in PHYSICS TODAY, January 1993, page 24). That analogy has now been taken a step further with the demonstration that a quantum dot interacts with nearby metallic leads in much the same way that a single magnetic impurity interacts with a surrounding metallic substance—in the phenomenon known as the Kondo effect.