Observation of triplet superconductivity in CoSi/TiSi heterostructures.

Unconventional superconductivity and, in particular, triplet superconductivity have been front and center of topological materials and quantum technology research. Here, we report our observation of triplet pairing in nonmagnetic CoSi/TiSi heterostructures on silicon. CoSi undergoes a sharp superconducting transition at a critical temperature ≃ 1.5 K, while TiSi is a normal metal. We investigate conductance spectra of both two-terminal CoSi/TiSi contact junctions and three-terminal T-shaped CoSi/TiSi superconducting proximity structures. Below , we observe (i) a narrow zero-bias conductance peak on top of a broad hump, accompanied by two symmetric side dips in the contact junctions, (ii) a narrow zero-bias conductance peak in T-shaped structures, and (iii) hysteresis in the junction magnetoresistance. These three independent and complementary observations point to chiral p-wave pairing in CoSi/TiSi heterostructures. The excellent fabrication compatibility of CoSi and TiSi with present-day silicon-based integrated-circuit technology suggests their potential use in scalable quantum-computing devices.