Superconductivity theories abound, but thus far none has led to a room-temperature superconductor. Now U.S. Department of Energy researchers believe a new theory—namely, that superconductivity is based on an undiscovered state of matter—may hold the key to a better understanding of the phenomenon.
"The involvement of an additional phase, once fully understood, might open up new possibilities for achieving superconductivity at even higher temperatures in these materials," said Ruihua He, a researcher at Lawrence Berkeley National Laboratory .
The new theory comes from U.S. Department of Energy researchers at Berkeley Lab, the University of California at Berkeley, and the SLAC National Accelerator Laboratory at Stanford University (Palo Alto, Calif.; SLAC's original name was the Stanford Linear Accelerator Center).
Together the labs coordinated separate experiments to zero in on whether superconductivity is based on a phase of matter other than the familiar solid, liquid or gas. The Stanford Synchrotron Radiation Lightsource used the magneto-optical Kerr effect, Berkeley Lab's Advanced Light Source team used angle-resolved photoemission spectroscopy, and a second group at Berkeley Lab used time-resolved reflectivity with a pump pulse from a laser.
The resulting detailed characterization of the same high-temperature superconductor (bismuth strontium calcium copper oxide) led to the theory that a separate state of matter exists at temperatures just above the superconducting state. Next, the researchers plan to explore the electronic properties of this new state of matter in a bid to discover how to extend superconductivity to room temperature.