Si-SSHQ · Realization and Characterization of Si-based Superconductor–Semiconductor Hybrid Quantum Circuits

Recently, cobalt disilicide (CoSi2) has emerged as a promising Si-based superconducting material with an exceptional lattice match with Si, leading to a nearly defect-free CoSi2/Si interface and extremely low 1/f resistance noise. Furthermore, recent studies have reported signatures of triplet correlations in superconducting CoSi2.In this proposal, I will realize various essential superconductor-semiconductor hybrid quantum circuits in the CoSi2/Si platform addressing longstanding challenges associated with the limited scalability of hybrid devices realized on other platforms. This will be mainly achieved by enhancing the Schottky barrier transparency at the CoSi2/Si interface, allowing sufficient Cooper pair tunneling to Si. This will enable realization of a scalable CoSi2/Si/CoSi2 Josephson field effect transistor (JoFET). Consequently, I will integrate the implemented JoFETs with the CoSi2 microwave cavity to realize a prototype for Si-based gatemon qubits.In parallel, I will also investigate the triplet correlation in CoSi2 by engineering CoSi2/Si-based CPS with a nearly perfect efficiency and measuring the magnitude of the triplet current. If the triplet current is sufficiently large to equalize the elastic cotunneling (ECT) and crossed Andreev reflection (CAR) amplitudes, it will provide a pathway for realization, characterization, and scaling up a triplet-based minimal Kitaev chain (TMKC), avoiding engineering platforms with strong spin-orbit fields or non-uniform magnetic fields.