Rutgers uses terahertz light to look inside superconductor vortices

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Physicists have found a new way to peer inside the tiny whirlpools that form in superconductors. Interesting Engineering reports that a team from Rutgers University, working with researchers in Tallinn, Estonia, used polarised terahertz light to study magnetic vortices in a superconductor, publishing their results in Physical Review Letters

When some superconductors are placed in a strong magnetic field, the field threads through them in tiny vortices. Particles trapped inside these vortex cores are difficult to study directly. The team says it has separated two groups of trapped particles for the first time

The material was an iron based tellurium selenium compound, grown as crystal films about 40 nanometres thick in Seongshik Oh's laboratory. The films were cooled to around minus 261 degrees Celsius in strong magnetic fields, and the team found that one group of particles responds only to left handed polarised light, and the other only to right handed light

The researchers estimated the size of the vortices, how long the particles' response lasts and how strongly the vortices resist changes in motion. Two versions of the material with different selenium content became superconducting at almost the same temperature, but one produced four times as many particles of the first group, while the other had an even split. Co-author Girsh Blumberg said understanding what vortices contain is key to designing better superconductors

This is fundamental materials science rather than quantum computing directly, although iron based superconductors are of interest for some exotic qubit ideas. The headline's claim about a 60 year old puzzle is not explained in the article. Still, a new experimental window into vortex cores is valuable

Could better superconductors come from studies like this? And are exotic materials still a promising route for future qubits?

Invisible light cracks 60-year-old superconductor whirlpool puzzleinterestingengineering.com