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

基于超导电路的量子信息是实现量子计算机最有前途的方向之一。量子技术面临的一个基本挑战是提高设备的相干持续时间。一种提高超导量子比特性能的方法是在硬件层面使用拓扑保护。这需要一种特殊类型的超导体，具有拓扑上非平凡的顺序参数，允许另一种方式来编码和保存信息。主要的挑战是确定新的（可获得的和制造友好的）材料符合任务的要求。手性超导体（SCs）由于其基态的拓扑性质，近年来作为在涡旋核心或样品边缘承载马约拉纳束缚态的有前途的平台受到了广泛的关注。马约拉纳束缚态被预测具有非阿贝尔统计，这使它们成为执行容错量子计算的候选者。这些手性态的序参量打破了时间反转对称性（TRS），在边缘或缺陷处表现出来，可以用介子自旋弛豫和极性克尔效应等探针检测到。在所有已知的超导体中，只有少数表现出TRS断裂的特征，而这种难以捉摸的手性相的候选者就更少了。最著名的是Sr2RuO4(SRO)，长期以来被认为具有p+ip对称性。然而，近年来SRO中超导性的性质受到了质疑，深入的研究仍在进行中。寻找具有手性超导性的新材料是最重要的。我们在这个项目中的主要目标是确定并提出一种合适的手性超导体作为量子信息应用的主要材料。(…）

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. (...)