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 superconductivity in nonmagnetic CoSi2/TiSi2 heterostructures on silicon. CoSi2 undergoes a sharp superconducting transition at a critical temperature Tc≈ 1.5 K, while TiSi2 is a normal metal. We investigate conductance spectra of both two-terminal CoSi2/TiSi2 tunnel junctions and three-terminal T-shaped CoSi2/TiSi2 superconducting proximity structures. We report an unexpectedly large spin-orbit coupling in CoSi2 heterostructures. Below Tc, we observe (1) a narrow zero-bias conductance peak on top of a broad hump, accompanied by two symmetric side dips in the tunnel junctions, (2) a narrow zero-bias conductance peak in T-shaped structures, and (3) hysteresis in the junction magnetoresistance. These three independent and complementary observations are indicative of chiral p-wave pairing in CoSi2/TiSi2 heterostructures. This chiral triplet superconductivity and the excellent fabrication compatibility of CoSi2 and TiSi2 with present-day silicon integrated-circuit technology facilitate full scalability for potential use in quantum-computing devices.
@article{arxiv.2012.13679,
title = {Observation of triplet superconductivity in CoSi$_2$/TiSi$_2$ heterostructures},
author = {Shao-Pin Chiu and C. C. Tsuei and Sheng-Shiuan Yeh and Fu-Chun Zhang and Stefan Kirchner and Juhn-Jong Lin},
journal= {arXiv preprint arXiv:2012.13679},
year = {2021}
}