Evrim Yazgin
Cosmos science journalist
Physicists investigating films of indium oxide found an odd quantum effect which they say is rare and could open up new avenues of research into quantum materials and superconductors.
The researchers used microwave spectroscopy to study the transition between superconducting and insulating states. They looked at the internal properties and behaviour of the indium oxide films.
One property they measured is the superfluid stiffness. This is used to gauge how resistant a material is to change from one phase to another.
Previous research has shown that superfluid stiffness varies smoothly (or continuously) as a material changes from a superconductor to an insulator.
Indium oxide – a substance known to have disordered and unusual properties – is an exception to this rule.
Rather than seeing the expected gradual shift in superfluid stiffness when they increased the temperature, the researchers found a sudden drop in indium oxide when a phase change occurred.
They also found that the critical temperature when the phase change occurred was not determined by how strongly bonded the Cooper pairs in the material were. Cooper pairs are pairs of electrons that move together and are responsible for the peculiar effects of superconductivity.
Instead, the critical temperature was determined by the superfluid stiffness. The researchers are unsure why.
“Our findings raise fundamental new questions about the role of disorder in quantum phase transitions and carry implications for superinductances in quantum circuits,” the researchers write in a paper published in Nature Physics.
They believe that the research could lead to more stable quantum materials.
