近日，美国斯坦福大学的Yusuke Iguchi与日本日本产业技术综合研究所（AIST）的Kunihiro Kihou以及瑞典皇家理工学院的Mats Barkman等人合作，并取得一项新进展。经过不懈努力，他们发现了超导涡旋携带通量量子的温度依赖部分。相关研究成果已于2023年6月1日在国际权威学术期刊《科学》上发表。

该研究团队利用扫描超导量子干涉仪（SQUID）磁测技术，研究人员对过掺杂空穴型Ba_1-xK_xFe₂As₂ (x = 0.77)中的孤立涡旋进行了探究。在多个位置上观察到的涡旋仅携带部分磁通量子，其大小随温度变化呈连续变化。这些特征被解释为具有非普遍量子化（分数化）磁通量的量子涡旋，其大小由多能带超导体的温度依赖参数确定。这种分数阶涡旋的可移动性和可操纵性可能在基于通量的流子逻辑计算方面具有应用前景。

据了解，磁场通过形成围绕着磁通量子大小的量子涡旋来穿透II型超导体块材。磁通量子是一个仅取决于基本常数的普遍量。

附：英文原文

Title: Superconducting vortices carrying a temperature-dependent fraction of the flux quantum

Author: Yusuke Iguchi, Ruby A. Shi, Kunihiro Kihou, Chul-Ho Lee, Mats Barkman, Andrea L. Benfenati, Vadim Grinenko, Egor Babaev, Kathryn A. Moler

Issue&Volume: 2023-06-01

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 Ba_1-xK_xFe₂As₂ (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.

DOI: abp9979

Source: https://www.science.org/doi/10.1126/science.abp9979