In the ever-developing field of quantum physics, new discoveries continue to shape our technological future, one of them being a breakthrough in superconductivity, where scientists have uncovered a previously unknown quantum state.
As it happens, superconductivity is a quantum property of certain materials to carry electricity without any resistance or energy loss, with the most familiar example of its utilization being the powerful magnets in MRI machines, according to an article by phys.org’s Kimm Fesenmaier on March 27.
Until now, these materials were only able to achieve superconductivity at extremely low temperatures, near absolute zero – a few tens of Kelvin or colder – but physicists have now discovered a new superconducting state, which might unlock the secrets of this powerful phenomenon, per a recent study.
How the superconductivity breakthrough happened
Notably, the team that achieved this was led by Stevan Nadj-Perge, professor of applied physics and materials science at California Institute of Technology and included Lingyuan Kong, AWS quantum postdoctoral scholar research associate, as well as other colleagues at Caltech.
According to Nadj-Perge, the recent discovery is a crucial step toward realizing the perennial dream of accomplishing superconductivity at room temperature:
“Understanding the mechanisms leading to the formation of superconductivity and discovering exotic new superconducting phases is not only one of the most stimulating pursuits in the fundamental study of quantum materials but is also driven by this ultimate dream of achieving room-temperature superconductivity.”
Specifically, in common metals, individual electrons collide with ions when traveling across the metal’s lattice structure that consists of oppositely charged ions, each collision leading to electrons losing energy and increasing electrical resistance. In contrast, electrons in superconductors are weakly attracted to each other and can form the so-called Cooper pairs.
These electrons then stay paired and don’t lose energy through collisions as long as they remain within a certain relatively small range of energy levels called the energy gap. Hence, superconductivity happens within this relatively small energy gap.
The Cooper-pair density modulation (PDM) state
Usually, this energy gap is the same at all locations within the material. However, since the 1960s, scientists have theorized that the energy gap in some superconducting materials could modulate in space, which means it would be stronger in some areas and weaker in others.
More recently – in the 2000s, physicists further developed this idea with the proposal of the pair density wave (PDW) state, which suggests that a superconducting state could appear, in which the energy gap modulates with a long wavelength, where the gap fluctuates between a larger and smaller measurement.
In the past decade, this concept attracted substantial experimental interest with various materials as potential hosts of a PDW state, including iron-based superconductors. Working with extremely thin flakes of an iron-based superconductor, Nadj-Perge’s team found a modulation of the superconducting gap with the smallest wavelength possible, matching the spacing of atoms in a crystal, which they named the Cooper-pair density modulation (PDM) state.
According to Kong, the lead author of the new paper:
“The observed gap modulation, reaching up to 40%, represents the strongest reported so far, leading to the clearest experimental evidence to date that gap modulation can exist even at the atomic scale.”
Speaking of quantum superconductivity, researchers at the Massachusetts Institute of Technology (MIT) have taken a massive step in quantum computing, developing an innovative interconnect device that paves the way for scalable, all-to-all communication between superconducting quantum processors.
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