Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state
Omargeldi Atanov, Wai Ting Tai, Ying-Ming Xie, Yat Hei Ng, Molly A. Hammond, Tin Seng Manfred Ho, Tsin Hei Koo, Hui Li, Sui Lun Ho, Jian Lyu, Sukong Chong, Peng Zhang, Lixuan Tai, Jiannong Wang, K. T. Law, Kang L. Wang, Rolf Lortz
Abstract
The ability to host Majorana modes, which are of great interest for more fault-tolerant quantum computation, keeps topological superconductors in the focus of research. Here, we report experimental data revealing 100-nm-wide quantum anomalous Hall insulator (QAHI) nanoribbons as a promising platform for the realization of zero-energy Majorana modes. One part of the nanoribbon is covered with superconducting niobium, while the other part is connected to a gold lead via two-dimensional QAHI regions. Andreev reflection spectroscopy reveals multiple in-gap conductance peaks in different devices. In the presence of an increasing magnetic field perpendicular to the film, the multiple-peak structure evolves into a single zero-bias conductance peak (ZBCP). Theoretical simulations suggest that the measurements are consistent with the scenario that the increasing field drives the nanoribbons from a multi-channel occupied regime to a single-channel regime, which is the necessary condition for the observation of zero-energy Majorana modes.