A two-site Kitaev chain in a two-dimensional electron gas

• Published in: Nature (London) Vol. 630; no. 8016; pp. 329 - 334
• Main Authors: ten Haaf, Sebastiaan L. D., Wang, Qingzhen, Bozkurt, A. Mert, Liu, Chun-Xiao, Kulesh, Ivan, Kim, Philip, Xiao, Di, Thomas, Candice, Manfra, Michael J., Dvir, Tom, Wimmer, Michael, Goswami, Srijit
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13.06.2024; Nature Publishing Group
• Subjects: 639/766/119/1000/1017; 639/766/119/1000/1018; 639/766/119/1003; 639/925/927/1064; Couplings; Electron gas; Electrons; Electrostatic properties; Energy; Energy spectra; Humanities and Social Sciences; Hybridization; Magnetic fields; multidisciplinary; Parameter robustness; Parity; Quantum dots; Science; Science (multidisciplinary); Spectroscopy; Spectrum analysis
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/s41586-024-07434-9

Artificial Kitaev chains can be used to engineer Majorana bound states (MBSs) in superconductor–semiconductor hybrids 1 – 4 . In this work, we realize a two-site Kitaev chain in a two-dimensional electron gas by coupling two quantum dots through a region proximitized by a superconductor. We demonstrate systematic control over inter-dot couplings through in-plane rotations of the magnetic field and via electrostatic gating of the proximitized region. This allows us to tune the system to sweet spots in parameter space, where robust correlated zero-bias conductance peaks are observed in tunnelling spectroscopy. To study the extent of hybridization between localized MBSs, we probe the evolution of the energy spectrum with magnetic field and estimate the Majorana polarization, an important metric for Majorana-based qubits 5 , 6 . The implementation of a Kitaev chain on a scalable and flexible two-dimensional platform provides a realistic path towards more advanced experiments that require manipulation and readout of multiple MBSs. We have implemented a two-site Kitaev chain in a two-dimensional electron gas by coupling quantum dots through Andreev bound states in a superconductor–semiconductor hybrid region.