2023-06-01 スウェーデン王立工科大学（KTH)
A new study by KTH Royal Institute of Technology and Stanford University revises of our understanding of quantum vortices in superconductors. Pictured, an artist’s depiction of quantum vortices. (Illustration: Greg Stewart, SLAC National Accelerator Laboratory)
◆研究者たちは、超伝導体内の渦が従来よりも広範な値に分割できることを発見しました。これは超伝導性の基本に新たな洞察をもたらし、超伝導電子機器に応用できる可能性があります。
◆これにより、量子渦は超伝導コンピュータで情報を運ぶための情報キャリアとして使用される可能性があります。この発見は、従来の理論を修正し、量子渦の本質を理解する上で重要です。
＜関連情報＞
- https://www.kth.se/en/om/nyheter/centrala-nyheter/tiny-quantum-electronic-vortexes-in-superconductors-can-circulate-in-ways-not-seen-before-1.1259759
- https://www.science.org/doi/10.1126/science.abp9979
超伝導渦は、温度依存的に磁束量子の分数を運ぶ Superconducting vortices carrying a temperature-dependent fraction of the flux quantum
Yusuke Iguchi,Ruby A. Shi,Kunihiro Kihou,Chul-Ho Lee,Mats Barkman,Andrea L. Benfenati,Vadim Grinenko,Egor Babaev and Kathryn A. Moler
Science Published:1 Jun 2023
DOI:https://doi.org/10.1126/science.abp9979
Abstract
Magnetic field penetrates type-II bulk superconductors by forming quantum vortices that enclose a magnetic flux equal to the magnetic flux quantum. The flux quantum is a universal quantity that depends only on fundamental constants. Here we investigate isolated vortices in the hole-overdoped Ba1−xKxFe2As2 (x = 0.77) by using scanning superconducting quantum interference device (SQUID) magnetometry. In many locations, we observed vortices that carried only part of a flux quantum, with a magnitude that varied continuously with temperature. We interpret these features as quantum vortices with non-universally quantized (fractional) magnetic flux whose magnitude is determined by the temperature-dependent parameters of a multiband superconductor. The demonstrated mobility and manipulability of the fractional vortices may enable applications in fluxonics-based computing.
