July 6, 2016 — Since the discovery of high-temperature superconductors—materials that can transport electricity with perfect efficiency at or near liquid nitrogen temperatures (minus-196 degrees Celsius)—scientists have been working to develop a theory that explains their essential physics. At the heart of this mystery is the pseudogap, a pivotal juncture on the path of superconducting copper oxides in which both insulating and conducting properties are present. Under these conditions, the conventional pathway to superconductivity is blocked, but a team led by Thomas Maier of Oak Ridge National Laboratory used the Titan supercomputer at ORNL to identify a possible alternative. Simulating a 16-atom cluster, the team measured a strengthening fluctuation of electronic antiferromagnetism, a specific magnetic ordering in which the spins of neighboring electrons point in opposite directions (up and down), as the system cooled. The findings add context to scientists’ understanding of the pseudogap and how superconductivity emerges from the phase.
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