An international team of physicists has identified unique quantum behavior in the compound YbSb2, composed of ytterbium and antimony. The study, published in Physical Review Letters, classifies this material as the first known type-I superconductor that exhibits signs of broken time-reversal symmetry.
Type-I superconductors are characterized by their ability to completely expel magnetic fields below a specific temperature threshold. Unlike type-II superconductors, which allow partial magnetic field penetration in the form of vortices, type-I materials were not previously associated with spontaneous magnetic field generation.
Researchers synthesized YbSb2 crystals and cooled them to near absolute zero. Using muon spin rotation, a technique capable of detecting extremely weak internal magnetic fields, the team observed the emergence of such fields upon the material's transition into a superconducting state.
Computer simulations suggest the presence of Majorana modes on the surface of YbSb2. While the team hypothesizes that the material could be a topological superconductor, further experimental verification is required to confirm these findings and the nature of the quantum state.
