Physicists have known about superconductors since 1911, but now it looks like the opposite - a superinsulator - might also exist, unnoticed until recently. An international team led by Argonne National Laboratory's Valerii Vinokur has published their findings in the April 3 issue of the journal Nature.

Image: Argonne scientist Valerii Vinokur
and Russian collaborator Tatyana Baturina examine
a graph of the resistance of the insulating film plotted
against the applied magnetic field.
(Argonne National Laboratory)

The superinsulator requires a very delicate balance to be achieved. Thin films of titanium nitride (normally a superconductor) apparently drop to zero electrical conductance when lowered below a certain critical temperature and placed in the presence of a magnetic field, the exact opposite of what occurs in standard superconductivity (which yields zero electrical resistance below a critical temperature).

Scientists have known that superconductors can turn into insulators, but only due to quantum phase transitions very near absolute zero. This new form of insulator extends over a range of temperatures up to nearly 70 millikelvin in a magnetic field of 0.9 tesla.

The theory behind these results poses some curious properties of quantum physics, as is usually the case. Essentially, they posit that electrical current and electrical voltage swap roles in the quantum system under these conditions. Plotting phase diagrams of current vs. magnetic field for superconductors and voltage vs. magnetic field for superinsulators result in a pair of phase diagrams which appear to be virtually identical, in fact! (Vinokur's team does just this in their Nature letter.)

In an analysis of the findings, Italian physicist Rosario Fazio says, "Vinokur and colleagues' observation and theory of superinsulation are crucial advances in our understanding of the collective properties of low-dimensional systems." Fazio goes on to speak about the extent to which further investigation into these topics needs to be performed.

One does have to wonder what technological insights we might gain from the intense study of how to create materials which can completely block the flow of electrical impulses.

Related Articles:

• Argonne National Laboratory - Newly discovered 'superinsulators' promise to transform materials research, electronics design
• Nature - Superinsulator and quantum synchronization (abstract available, full text requires subscription or payment)
• Nature - Condensed-matter physics: Opposite of a superconductor (subscription or payment required)
• ScienceDaily.com - Newly Discovered Fundamental State Of Matter, A Superinsulator, Has Been Created
• PhysicsWorld.com - Physicists discover the 'superinsulator'
• Definition - Superconductor