Ultrahigh Supercurrent Density in a Two-Dimensional Topological Material

Published November 16, 2023

a. Schematic illustration of a 1T′-WS2 device and the rotation experiment setup. b. Magnetic field dependence of the normalized resistance of the 1T′-WS2 device at T = 0.33 K with different in-plane rotation angles φ. c. The φ-dependence of the upper critical field. The green dashed line indicates the Pauli limit.

a. Schematic illustration of a 1T′-WS₂ device and the rotation experiment setup. b. Magnetic field dependence of the normalized resistance of the 1T′-WS₂ device at T = 0.33 K with different in-plane rotation angles φ. c. The φ-dependence of the upper critical field. The green dashed line indicates the Pauli limit.

Research on a tungsten disulfide material (1T’-WS₂) reveals a superconducting state that is able to carry an incredibly large amount of current within its superconducting layers - exceeding all other known two-dimensional superconductors.

What did scientists discover?

The combination of extremely high DC magnetic fields up to 41T and an in-situ sample rotation stage allowed the observation of a strongly anisotropic superconducting state that had not been observed previously. Additionally, MagLab users found in this material (1T′-WS₂) an unprecedentedly high superconducting critical current density (17MA/cm² at 0T) that exceeds all other known two-dimensional superconductors. By comparison, this critical current density here is 15 to 70 times larger is found in the superconductors presently used to commercially build superconducting magnets.

The band structure obtained via angle-resolved photoemission spectroscopy and first-principles calculations points to 1T′-WS₂ possessing a Z₂ topological invariant.

Why is this important?

High supercurrent densities in materials result in machines and devices that are efficient and much smaller, such as high-field magnets and high-performance superconducting spintronics. Furthermore, the simultaneous presence of topology and superconductivity in 1T′-WS₂ establishes 1T′-WS₂ as a topological superconductor candidate which is a favorable environment for non-Abelian anyons that could enable the construction of a fault tolerant topological quantum computer.

Who did the research?

Qi Zhang^1*†, Md Shafayat Hossain^1*†, Brian Casas², Wenkai Zheng², Zi-Jia Cheng¹, Zhuangchai Lai^3,4, Yi-Hsin Tu⁵, Guoqing Chang⁶, Yao Yao³, Siyuan Li³, Yu-Xiao Jiang¹, Sougata Mardanya⁵, Tay-Rong Chang⁵, Jing-Yang You⁷, Yuan-Ping Feng⁷, Guangming Cheng¹, Jia-Xin Yin¹, Nana Shumiya¹, Tyler A. Cochran1, Xian P. Yang¹, Maksim Litskevich¹, Nan Yao¹, Kenji Watanabe⁸, Takashi Taniguchi⁸, Hua Zhang^3,†, Luis Balicas², M. Zahid Hasan^1,9

¹Princeton University; ²National High Magnetic Field Laboratory; ³City Univ. of Hong Kong; ⁴The Hong Kong Polytechnic Univ.; ⁵National Cheng Kung Univ.; ⁶Nanyang Technological University; ⁷National Univ. of Singapore; ⁸National Institute for Materials Science; ⁹Lawrence Berkeley National Laboratory

Why did they need the MagLab?

To observe the anisotropic superconducting state with high critical field, it was necessary to cool the sample down to 0.3K and apply very high magnetic fields (well above 30T). Indeed, the MagLab’s 41T resistive magnet with its high-precision in-situ rotator was essential to this experiment.

Details for scientists

View or download the expert-level Science Highlight, Ultrahigh Supercurrent Density in a Two-Dimensional Topological Material
Read the full-length publication, Ultrahigh supercurrent density in a two-dimensional topological material, in Physical Review Materials

Funding

This research was funded by the following grants: Z. M. Hasan (GBMF4547；DOE/BES DE-FG-288 02-05ER46200); L. Balicas (DE-SC0002613); N. Yao (DMR-2011750); G.S. Boebinger (NSF DMR-1644779)

For more information, contact Tim Murphy.