Bordin Alberto, Liu Chun-Xiao, Dvir Tom, Zatelli Francesco, Ten Haaf Sebastiaan L D, van Driel David, Wang Guanzhong, van Loo Nick, Zhang Yining, Wolff Jan Cornelis, Van Caekenberghe Thomas, Badawy Ghada, Gazibegovic Sasa, Bakkers Erik P A M, Wimmer Michael, Kouwenhoven Leo P, Mazur Grzegorz P
QuTech and Kavli Institute of NanoScience, Delft University of Technology, Delft, The Netherlands.
Quantum Machines, Tel Aviv-Yafo, Israel.
Nat Nanotechnol. 2025 Mar 31. doi: 10.1038/s41565-025-01894-4.
Majorana zero modes are non-Abelian quasiparticles predicted to emerge at the edges of topological superconductors. A one-dimensional topological superconductor can be realized with the Kitaev model-a chain of spinless fermions coupled via p-wave superconductivity and electron hopping-which becomes topological in the long-chain limit. Here we realize a three-site Kitaev chain using semiconducting quantum dots coupled by superconducting segments in a hybrid InSb/Al nanowire. We investigate the robustness of Majorana zero modes under varying coupling strengths and electrochemical potentials, comparing two- and three-site chains realized within the same device. We observe that extending the chain to three sites enhances the stability of the zero-energy modes, especially against variations in the coupling strengths. This experiment lacks superconducting phase control, yet numerical conductance simulations with phase averaging align well with our observations. Our results demonstrate the scalability of quantum-dot-based Kitaev chains and its benefits for Majorana stability.
马约拉纳零模是预测会出现在拓扑超导体边缘的非阿贝尔准粒子。一维拓扑超导体可以用基塔耶夫模型来实现，即通过p波超导性和电子跳跃耦合的无自旋费米子链，在长链极限下它会变成拓扑的。在这里，我们使用混合InSb/Al纳米线中由超导段耦合的半导体量子点实现了一个三格点的基塔耶夫链。我们研究了在不同耦合强度和电化学势下马约拉纳零模的稳健性，比较了在同一器件中实现的两格点和三格点链。我们观察到将链扩展到三个格点会增强零能模的稳定性，特别是抵抗耦合强度变化的能力。这个实验缺乏超导相位控制，但通过相位平均的数值电导模拟与我们的观察结果吻合得很好。我们的结果证明了基于量子点的基塔耶夫链的可扩展性及其对马约拉纳稳定性的益处。
