Chiral superconductivity in the van-der-Waals heterostructure 4Hb-TaS2

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Superconducting circuit-based quantum information is one of the most promising directions toward the realization of a quantum computer. A fundamental challenge for quantum technology is improving the coherence duration of devices. One proposed way to improve the performance of superconducting qubits is to use topological protection at the hardware level. This requires a special type of superconductor, with topologically non-trivial order parameter, that allows an alternative way to encode and preserve information. The main challenge is to identify new (accessible and fabrication-friendly) materials that qualify for the task. Chiral superconductors (SCs) have received much attention in recent years as a promising platform for hosting Majorana-bound states in the vortex cores or at sample edges, due to the topological nature of their ground state. The Majorana bound states are predicted to possess non-Abelian statistics, which makes them candidates for performing fault-tolerant quantum computations. The order parameter of these chiral states breaks time-reversal symmetry (TRS), which manifests itself at edges or defects and can be detected with probes such as muon spin relaxation and polar Kerr effect. Of all known superconductors, only a few exhibit signatures of TRS breaking, and even fewer are candidates for this elusive chiral phase. The best known is Sr2RuO4(SRO), long thought to exhibit p+ip symmetry. Recently, however, the nature of superconductivity in SRO has been questioned, and intensive research is still underway. Finding new materials possessing chiral superconductivity is of the highest importance. Our primary goal in this project is to identify and put forward a suitable chiral superconductor as a leading material for quantum information applications. (...)