It often happens in science that research focused on one phenomenon results in the unexpected discovery of a new effect that is much more exciting and important. In 1995 a case of this serendipity occurred with my research group, then at the NEC Research Institute in Princeton, N.J.
We were studying the properties of a microelectronics structure called a semiconductor superlattice, which consisted of layers of gallium arsenide and gallium aluminum arsenide stacked like a club sandwich. We knew that this superlattice had very interesting electrical properties. In particular, we were investigating how the thickness of the layers determined whether the superlattice behaved as a metal, with low electrical resistance, or as an insulator, with high resistance. We immersed the system in a magnetic field, a procedure that enabled us to study dynamical processes involving the electrons in the superlattice.
This article was originally published with the title Magnetic Field Nanosensors.