Enhanced and modulable induced superconducting gap and effective Land\'e g-factor in Pb-InSb hybrid devices

Guoan Li; Xiaofan Shi; Ziwei Dou; Guang Yang; Jiayu Shi; Marco Rossi; Ghada Badawy; Yuxiao Song; Ruixuan Zhang; Yupeng Li; Zhiyuan Zhang; Anqi Wang; Xingchen Guo; Xiao Deng; Bingbing Tong; Peiling Li; Zhaozheng Lyu; Guangtong Liu; Fanming Qu; Erik P. A. M. Bakkers; Michał P. Nowak; Paweł Wójcik; Li Lu; Jie Shen

arXiv · 2506.03563

Enhanced and modulable induced superconducting gap and effective Land\'e g-factor in Pb-InSb hybrid devices

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Abstract

The hybrid system of a conventional superconductor (SC) on a semiconductor (SM) nanowire with strong spin-orbit coupling (SOC) represents a promising platform for achieving topological superconductivity and Majorana zero modes (MZMs) towards topological quantum computation. While aluminum (Al)-based hybrid nanowire devices have been widely utilized, their limited superconducting gap and intrinsic weak SOC as well as small Land\'e g-factor may hinder future experimental advancements. In contrast, we demonstrate that lead (Pb)-based hybrid quantum devices exhibit a remarkably large and hard proximity-induced superconducting gap, exceeding that of Al by an order of magnitude. By exploiting electrostatic gating to modulate wavefunction distribution and SC-SM interfacial coupling, this gap can be continuously tuned from its maximum value (~1.4 meV, matching the bulk Pb gap) down to nearly zero while maintaining the hardness. Furthermore, magnetic-field-dependent measurements reveal a radial evolution of the gap structure with anti-crossing feature, indicative of strong SOC and huge effective g-factors up to 76. These findings underscore the superior functionality of Pb-based hybrid systems, significantly advancing their potential for realizing and stabilizing MZMs and the further scalable topological quantum architectures.

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Guoan Li, Xiaofan Shi, Ziwei Dou, Guang Yang, Jiayu Shi, Marco Rossi, Ghada Badawy, Yuxiao Song, Ruixuan Zhang, Yupeng Li, Zhiyuan Zhang, Anqi Wang, Xingchen Guo, Xiao Deng, Bingbing Tong, Peiling Li, Zhaozheng Lyu, Guangtong Liu, Fanming Qu, Erik P. A. M. Bakkers, Michał P. Nowak, Paweł Wójcik, Li Lu, Jie Shen. 2025-06-04. Enhanced and modulable induced superconducting gap and effective Land\'e g-factor in Pb-InSb hybrid devices. https://arxiv.org/abs/2506.03563

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