BRIEF: A Breakthrough Tool for Studying Superconductors
Greg Stewart/SLAC National Accelerator Laboratory
(Inside Science) -- Researchers have found a way to measure the vibration of electrons with unprecedented precision -- with a frame rate of several million billion times per second, and resolution a billionth of the width of a human hair.
The new approach could help scientists understand why certain materials have exotic properties, such as the ability to conduct electricity with zero resistance at low temperatures.
Many so-called superconductors, especially those that work at comparably higher temperatures, cannot be explained with established theories. One such example is the material iron selenide. About five years ago, scientists in China found that when they lay a thin layer of iron selenide on top of a specific material made of strontium, titanium and oxygen, the iron selenide superconducts up to -213 degrees Celsius, 52 degrees warmer than stand-alone iron selenide. Later studies revealed a possible connection between this increase in superconducting temperature and the way vibrations from the underlying material were introduced to the iron selenide's electrons, a phenomenon known as electron-phonon coupling. However, the presence of many other effects complicated efforts to understand this relationship.
To circumvent this obstacle, a team of researchers led by scientists from the SLAC National Accelerator Laboratory in California introduced the several-trillion-times-per-second vibrations with a laser, then used an existing technique to detect the electrons' movement.
The researchers found that the relationship between electrons and their vibrations plays an even larger role in superconductivity than previously thought.
"The nature of research is that it often takes you to unexpected directions," said Zhi-Xun Shen, a physicist from Stanford University in California who was involved in the study. "How this new insight can lead to material design is something we'll have to work out."