PALO ALTO, Ca. – research team at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University has finally revealed that fourth signature with precise, high-resolution measurements made with angle-resolved photoemission spectroscopy, or ARPES, which uses light to eject electrons from the material. Measuring the energy and momentum of those ejected electrons reveals how the electrons inside the material behave.
In a paper published recently in Nature, the team confirmed that the cuprate material they studied, known as Bi2212, made the transition to a superconducting state in two distinct steps and at very different temperatures.
“Now we know what happens at the superconducting transition in very fine detail, and we can think about how to make that happen at higher temperatures,” said Sudi Chen, who led the study while a PhD student at Stanford. “That’s a very practical direction.”
Stanford Professor Zhi-Xun Shen, an investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) at SLAC who supervised the research, said, “This is the climax of 15 years of scientific detective work in trying to understand the electronic structure of these materials, and it provides the missing link for a holistic picture of unconventional superconductivity. We knew these materials should produce distinctive spectroscopic signatures as the paired electrons coalesce into a quantum condensate; the amazing thing is that it took so long to find it.”
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