Yufan Li, Xiaoying Xu, M.-H. Lee, M.-W. Chu, C. L. Chien.

Science, Vol. 366, Issue 6462, pp. 238-241 (2019)

https://science.sciencemag.org/content/366/6462/238

Abstract

Magnetic flux quantization is one of the defining properties of a superconductor. We report the observation of half-integer magnetic flux quantization in mesoscopic rings of superconducting β-Bi₂Pd thin films. The half-quantum fluxoid manifests itself as a π phase shift in the quantum oscillation of the superconducting critical temperature. This result verifies unconventional superconductivity of β-Bi₂Pd and is consistent with a spin-triplet pairing symmetry. Our findings may have implications for flux quantum bits in the context of quantum computing.