The new spectroscopy technique measures electron energy levels with 1,000 times greater resolution than previous methods, an advance that has "tremendous power to tell you what the electrons are doing," said MIT physics professor Ray Ashoori, author of a paper on the work published in the July 12 issue of Nature. This technique has already revealed some surprising behavior, and the researchers believe it will shed new light on many physical phenomena involving electrons.
Here's the exact citation to this work:
O. E. Dial et al., Nature v.448, p.176 (2007).
Properties of electrons in 2D is quite important because many exotic systems are thought to be 2D. This includes the yet-unsolved high-Tc superconductors, where the charge carriers are believed to be in the Cu-O planes.