Nanoscale ultra-thin film network provides a novel approach to enhance the critical field of superconductors
The ability for a superconductor to survive under high magnetic fields is crucial for its applications. A team of researchers from US and Academia Sinica has found a method to boost the critical field of superconductor. The researchers used the molecular beam epitaxial (MBE) technique to grow the single crystalline Pb into a nano-mesh of 2nm thickness. By using low temperature scanning tunneling microscope, mutual inductance measurements and magneto-transport measurements, the researchers found that the Pb nano-mesh maintains strong global phase rigidity, thus retaining the Tc close to that of a bulk crystal. The parallel critical field is significantly higher than the Clogston limit as a direct consequence of ultra-thin geometry and strong spin orbital coupling. In the perpendicular field, the orbital pair breaking is also quenched until the magnetic length becomes smaller than the lateral dimension of the nano-mesh. The inverse correlation of the lateral width and local HC⏊ points to a possibility to achieve much higher HC⏊. This work demonstrates that superconductivity pair breaking can be significantly suppressed by nanoscale engineering and opens new strategies to optimize superconducting quantum devices.
These findings have now been published in the journal Nature Communication. The collaboration consists of Prof. Chih-Kang Shih (University of Texas), Prof. Allan MacDonald (University of Texas), Prof. Hua Chen (Colorado State University), Prof. Philip Adams (Louisiana State University) and the Surface Science Group at the Institute of Physics, Academia Sinica (Dr. Syu-You Guan, Dr. Tien-Ming Chuang and Director Chia-Seng Chang). The work at Institute of Physics is supported by Ministry of Science and Technology and Academia Sinica. Dr. Tien-Ming Chuang also acknowledges the support from Kenda Foundation and Dr. Syu-You Guan is now the recipient of postdoctoral fellowship from Academia Sinca.
More information: Nam et al., Nature Communications 9, 5431 (2018).
Journal Links: https://doi.org/10.1038/s41467-018-07778-7
WebSite: http://www.phys.sinica.edu.tw/~nano/
WebSite: http://www.phys.sinica.edu.tw/~nano/