London
Lecture 2004
MYRIAM P. SARACHIK
City
College of New York
Member
NAS
APS President
2003
Metal-Insulator Transitions
Transitions between metallic and
insulating behavior occur in many materials as some parameter of the system is
varied. Examples of metal-insulator transitions in bulk,
three-dimensional semiconductors will be shown. Based on both theory and
experiment, however, it was believed for many years that no metallic phase is
possible in two dimensions (systems that exists on a plane or a surface).
It was therefore a surprise and a source of great controversy when behavior
characteristic of a metal was observed. Is there a true metallic phase in
two dimensions? Do these observations signal exciting new physics or can
they be explained by extending known physics into a new regime? A brief
history will be presented and the current situation will be discussed.
New results will be shown if time permits.