Observation of triplet superconductivity in CoSi 2 /TiSi 2 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 ₂ /TiSi ₂ heterostructures on silicon. CoSi ₂ undergoes a sharp superconducting transition at a critical temperature T _c ≃ 1.5 K, while TiSi ₂ is a normal metal. We investigate conductance spectra of both two-terminal CoSi ₂ /TiSi ₂ contact junctions and three-terminal T-shaped CoSi ₂ /TiSi ₂ superconducting proximity structures. Below T _c , 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 ₂ /TiSi ₂ heterostructures. The excellent fabrication compatibility of CoSi ₂ and TiSi ₂ with present-day silicon-based integrated-circuit technology suggests their potential use in scalable quantum-computing devices.
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