Enhanced Majorana stability in proximitized quantum dots
Francesco Zatelli1, Tom Dvir1, David van Driel1, Di Xu1, Guanzhong Wang1, Chun-Xiao Liu1, Alberto Bordin1, Bart Roovers1, Grzegorgz P. Mazur1, Nick van Loo1, Jan C. Wolff1, Sasa Gazibegovic2, Ghada Badawy2, Erik P. A. M. Bakkers2, Michael Wimmer1, Leo P. Kouwenhoven1
1 QuTech and Kavli Institute of NanoScience, Delft University of Technology, 2600 GA Delft, The Netherlands
2 Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
The recent realization of a two-site Kitaev chain [1], and the formation of "Poor man's Majorana" [2] states within, provide a path forward in the field of topological superconductivity [3]. To use such states as the building blocks for a parity qubit and to create longer Kitaev chains, it is necessary to increase the reproducibility of the two-dot system and to increase the robustness of the Majorana states to external perturbations. Here we use two proximitized quantum dots as the basis for the two-site Kitaev chain [4]. We show that in this manner, we enhance the interaction strength between the two quantum dots and form Poor man's Majorana states which are an order of magnitude more stable to gate fluctuations than what was previously reported. This approach does not depend on fine-tuning energy scales to succeed, making it a cross-platform generic approach to forming a Kitaev chain.
[1] Dvir, T., Wang, G., van Loo, N., et al. Realization of a minimal Kitaev chain in coupled quantum dots. arXiv:2206.08045. (2022).
[2] Leijnse, M., and Flensberg, K. Parity qubits and poor man’s Majorana bound states in double quantum dots. Phys. Rev. B, 86(13), 134528. (2012).
[3] Sau, J., Sarma, S. Realizing a robust practical Majorana chain in a quantum-dot-superconductor linear array. Nat Commun 3, 964 (2012).
[4] Tsintzis, A., Souto, R. S., and Leijnse, M. Creating and detecting poor man’s Majorana bound states in interacting quantum dots. Phys. Rev. B, 106(20), L201404. (2022).