A team of scientists from the University of Waterloo has discovered new properties of superconductivity that show potential to help researchers create a theory on how the process begins at the atomic level. Eventually, the findings could also help humans harness the potential of materials that can provide efficient energy storage and levitating trains.
The team discovered that the electron clouds found in superconducting materials can form aligned and directional orders, an ability referred to as nematicity.
"It has become apparent in the past few years that the electrons involved in superconductivity can form patterns, stripes or checkerboards, and exhibit different symmetries - aligning preferentially along one direction," Michel Hawthorn, who participated in the research, said in a press release.
"These patterns and symmetries have important consequences for superconductivity - they can compete, coexist or possibly even enhance superconductivity," he added.
The findings in the current study are the most direct evidence thus far that electronic nematicity is present in all cuprate high-temperature superconductors.
"In this study, we identify some unexpected alignment of the electrons - a finding that is likely generic to the high temperature superconductors and in time may turn out be a key ingredient of the problem," Hawthorn said.
Using a technique called soft X-ray scattering, the team examined electron scattering in specific layers in the cuprate crystalline structure, specifically individual cuprate (CuO2) planes. These planes, where electronic nematicity occurs, were compared to the crystalline distortion in between each of the CuO2 planes. The results revealed that electronic nematicity occurs when the electronic orbitals drop below a critical point.
The findings also revealed that the areas of specific cuprates possess bunches of electrons that form high- and low- density clouds, something that it specific to superconducting materials that can form aligned and directional orders.
"Future work will tackle how electronic nematicity can be tuned, possibly to advantage, by modifying the crystalline structure," Hawthorn concluded.
The findings were published in the Feb. 5 issue of Science.
