Electrical Step‐Edge Contact to a Topological Superconductor Candidate 2M‐WS <sub>2</sub>

A topological superconductor (TSC), characterized by a topologically nontrivial bulk state and protected gapless boundary states, is a promising platform for hosting Majorana bound states. However, many TSCs are environmentally sensitive, especially when thinned to 2D atomic layers. This instability poses a major challenge for integrating TSCs into electronic devices. Addressing it requires full encapsulation and high-quality electrical contact to the TSC layer, which have not yet been achieved. Here, a novel contact geometry is demonstrated for an encapsulated topological superconductor candidate, 2M-WS<sub>2</sub>, where metal electrodes contact the exposed step-like edges with a width of only a few nanometers. This structure yields exceptionally low contact resistance (R<sub>C</sub>), down to ∼ 670 Ω·µm for a single unit and ∼ 65 Ω·µm for a six-unit 2M-WS<sub>2</sub> device. Below the superconducting critical temperature (T<sub>C</sub>), the TSC-metal interface becomes highly transparent, as evidenced by the Andreev reflection. Furthermore, the step-edge contact prevents contamination during fabrication, enabling unprecedentedly high-quality devices. In encapsulated 2M-WS<sub>2</sub>, twofold rotational symmetry of the critical current (I<sub>C</sub>) and multiple anomalous peaks are observed in the differential resistance (dV/dI). The anisotropic I<sub>C</sub> originates from Fermi velocity variations along in-plane lattice directions, while the anomalous peaks suggest multigap superconductivity in 2M-WS<sub>2</sub>. These results reveal the intrinsic properties of 2M-WS<sub>2</sub> and offer a new path toward high-performance TSC-based electronics.

Authors

Institutions

Publication Details

Journal
Advanced Science
Published
2025-11-14
DOI
https://doi.org/10.1002/advs.202508242
Primary Topic
Topological Materials and Phenomena
Type
article
Field-Weighted Citation Impact
0.00

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Electrical Step‐Edge Contact to a Topological Superconductor Candidate 2M‐WS 2

Lede Xian, Yuqiang Fang, Lin Gu, Fuqiang Huang et al.
Advanced Science
Topological Materials and Phenomena
article

Electrical Step‐Edge Contact to a Topological Superconductor Candidate 2M‐WS 2

Lede Xian, Yuqiang Fang, Lin Gu, Fuqiang Huang, Yuzheng Guo, Takashi Taniguchi, Yangchen He, Daniel Rhodes, Kenji Watanabe, Hailing Guo, Yujian Zhu, Zhongkai Liu, Junwei Song, Dongdong An, Qikang Gan, Xinyan Li, Han Gao, Lei Wang, Yiwei Li, Qinghua Zhang
article en

Abstract

A topological superconductor (TSC), characterized by a topologically nontrivial bulk state and protected gapless boundary states, is a promising platform for hosting Majorana bound states. However, many TSCs are environmentally sensitive, especially when thinned to 2D atomic layers. This instability poses a major challenge for integrating TSCs into electronic devices. Addressing it requires full encapsulation and high-quality electrical contact to the TSC layer, which have not yet been achieved. Here, a novel contact geometry is demonstrated for an encapsulated topological superconductor candidate, 2M-WS<sub>2</sub>, where metal electrodes contact the exposed step-like edges with a width of only a few nanometers. This structure yields exceptionally low contact resistance (R<sub>C</sub>), down to ∼ 670 Ω·µm for a single unit and ∼ 65 Ω·µm for a six-unit 2M-WS<sub>2</sub> device. Below the superconducting critical temperature (T<sub>C</sub>), the TSC-metal interface becomes highly transparent, as evidenced by the Andreev reflection. Furthermore, the step-edge contact prevents contamination during fabrication, enabling unprecedentedly high-quality devices. In encapsulated 2M-WS<sub>2</sub>, twofold rotational symmetry of the critical current (I<sub>C</sub>) and multiple anomalous peaks are observed in the differential resistance (dV/dI). The anisotropic I<sub>C</sub> originates from Fermi velocity variations along in-plane lattice directions, while the anomalous peaks suggest multigap superconductivity in 2M-WS<sub>2</sub>. These results reveal the intrinsic properties of 2M-WS<sub>2</sub> and offer a new path toward high-performance TSC-based electronics.

Advanced ScienceVol. 13(2)
University of Wisconsin System (US), University of Wisconsin–Madison (US), Shanghai Jiao Tong University (CN), Chinese Academy of Sciences (CN), National Institute for Materials Science (JP), ShanghaiTech University (CN), Wuhan University (CN), Jiangsu Province Blood Center (CN), Institute for Advanced Study (DE), Collaborative Innovation Center of Advanced Microstructures (CN), Max Planck Institute for the Structure and Dynamics of Matter (DE), Institute of Physics (CN), Shanghai Institute of Ceramics (CN), Tsinghua University (CN)
Ministry of Education, Culture, Sports, Science and Technology, National Natural Science Foundation of China, Government of Jiangsu Province, Science and Technology Commission of Shanghai Municipality, Natural Science Foundation of Jiangsu Province, Nanjing University, Shanghai Rising-Star Program, Japan Society for the Promotion of Science, National Key Research and Development Program of China, Basic and Applied Basic Research Foundation of Guangdong Province
Openalex Percentile: Top 73%
Topological Materials and Phenomena
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.