Oxide interfaces , perspectives for new physics and devices
Jack Harris,
Departments of Physics and Applied Physics, Yale University
One
of the most remarkable predictions of the quantum theory of electronic circuits
is that a small loop of resistive metal can have a perpetual current flowing in
it in the absence of any voltage. This "persistent" current is directly
analogous to the motion of electrons around the nucleus of an atom. The
prediction that it could be observed in real electrical circuits generated
considerable excitement... 25 years ago. Since then, experiments in this area
have produced confusing results at odds with theory and even with each other. We
have addressed this long-standing controversy by developing a new type of
detector for persistent currents which offers much greater sensitivity and a
less-invasive measurement than was previously possible. Our results have made
possible a detailed comparison between experiment and theory. I will describe
these results, which seem to give the clearest picture yet of persistent
currents in resistive metals. I will also describe how persistent currents can
now be applied to resolve outher outstanding questions in many-body condensed
matter physics.