Rutgers team separates two quasiparticle types in superconductor vortices

A Rutgers-led team used the handedness of circularly polarized terahertz light to separately measure electron-like and hole-like quasiparticles inside the vortex cores of the iron-based superconductor FeTe₁₋ₓSeₓ. The results, published in Physical Review Letters, address a question first posed in 1964.

• The method relies on left- and right-handed circular polarization of terahertz light
• FeTe₁₋ₓSeₓ films were cooled to 3.5 K in magnetic fields up to 15 Tesla
• The material's superconducting coherence length is 1.7–2.7 nm
• The work matters for topological quantum computing research