“The source of this extraordinary phenomenon is slowly but surely running out of places to hide.”

Brookhaven physicist Ivan Bozovic, talking about high-temperature superconductivity – or HTS, as we like to call it. Nobody knows quite how HTS materials can carry electric current with perfect efficiency, but we’re honing in on just what makes them tick.

The latest hunt for the elusive mechanism behind HTS involved picosecond laser pulses riding waves across custom-grown electron seas. That sounds confusing, we know, but hang in there.

A leading theory suggests that fleeting fluctuations in a material’s electron density might actually drive superconductivity. These fluctuations—called charge-density waves—could create the subatomic conditions that allow for that long-sought, loss-free energy. Alas, it was not meant to be.

In an experiment that refuted this theory, MIT physicists applied their laser mastery to the atomically perfect materials made in clean rooms here at Brookhaven to pinpoint the rise, fall, and drift of the subatomic waves. One laser pulse generated a wave in the material, and then a second pulse struck the wave to measure its dimensions—all within just trillionths of a second. 

The results revealed that these subtle electron waves probably have nothing to do with superconductivity. As the temperature of the material increased, the charge-density waves actually vanished entirely while the superconducting behavior continued. The mystery isn’t solved, but as Bozovic said, we’re getting close to cornering the culprit.