A specific superconducting crystal acts as a one-way valve for electricity without any external power or magnetic fields.
Superconductors allow electricity to flow perfectly in any direction without resistance. This specific material breaks a fundamental law called time-reversal symmetry, which ensures electricity behaves the same way forward and backward. Electricity flows easily in one direction but hits a wall when trying to go the other way. Bulky magnets are required to force this kind of behavior, but this crystal does it inherently. This discovery paves the way for superconducting computers that are faster and use a fraction of the energy of current silicon chips. A simple piece of matter now acts as a natural diode that could redefine how we build quantum electronics.
Signatures of time-reversal-symmetry breaking in multiband 2H-TaS2 revealed by zero-field Josephson nonreciprocity
arXiv · 2605.00477
Superconductors that spontaneously break time-reversal symmetry host complex order parameters and are widely regarded as a hallmark of unconventional superconductivity. Whether such symmetry breaking can also arise in superconductors with nominally isotropic spin-singlet pairing remains an open question. Here we report a zero-field Josephson diode effect in noncentrosymmetric 2H-TaS2/2H-NbSe2 van der Waals junctions. The diode efficiency shows no systematic correlation with supercurrent amplitud