YbSb2 superconductor discovered to break time-reversal symmetry

Physicists have identified a unique property in the type-I superconductor ytterbium diantimonide (YbSb2), which spontaneously breaks time-reversal symmetry. This phenomenon, where a system behaves differently whether time flows forward or backward, was previously thought to be a hallmark exclusive to unconventional type-II superconductors.

Researchers from the Indian Institute of Science Education and Research (IISER) Bhopal synthesized single crystals of YbSb2 and observed that the material enters a superconducting state at approximately 0.95 Kelvin. Unlike type-II superconductors that allow magnetic flux to enter in organized regions, YbSb2 behaves as a type-I superconductor, expelling magnetic fields in its Meissner state and entering an intermediate state at higher magnetic fields.

This discovery, published in Physical Review Letters, suggests a new pathway for exploring exotic superconducting states and could potentially influence the development of future quantum computing designs.