Metals turn into insulators using a new quantum switch

A study written by Researchers at the University of British Columbia will now change our understanding of how electrical conduction works. It was published in Nature Physics recently. By leveraging the interaction between an electron’s spin and its orbital rotation around the nucleus it demonstrates a new way to precisely control electrical currents.

In a Mott insulator, there is no free flow of electrons due to electrostatic repulsion – the electrons don’t get too close to one another and hence a traffic jam is created.The traffic jam is reduced by reducing the strength of repulsion between electrons or by changing the number of electrons. These two were the only two known methods before this breakthrough research was published.

Lead author of the study, Zwartsenberg, found that the electrons could be slowed down by coupling the spin to the orbital angular momentum. This causes the electrons to become sensitive to one another’s presence, solidifying the traffic jam”. They just reduced the spin-orbit coupling which eases the traffic jam and hence an insulator turns into a metal.

Co-author Andrea Damascellistated that the result was a really exciting one at the level of fundamental physics.