Seoane Souto Rubén, Kuzmanovski Dushko, Sardinero Ignacio, Burset Pablo, Balatsky Alexander V
Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.
Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, 106 91 Stockholm, Sweden.
J Low Temp Phys. 2024;217(1-2):106-120. doi: 10.1007/s10909-024-03176-0. Epub 2024 Jun 25.
Superconductivity and magnetism are competing effects that can coexist in certain regimes. Their co-existence leads to unexpected new behaviors that include the onset of exotic electron pair mechanisms and topological phases. In this work, we study the properties of a Josephson junction between two spin-split superconductors. The spin-splitting in the superconductors can arise from either the coupling to a ferromagnetic material or an external magnetic field. The properties of the junction are dominated by the Andreev bound states that are also split. One of these states can cross the superconductor's Fermi level, leading to a ground-state transition characterized by a suppressed supercurrent. We interpret the supercurrent blockade as coming from a dominance of p-wave pairing close to the junction, where the electrons are at both sides. To support this interpretation, we analyze the different pairing channels and show that p-wave pairing is favored in the case where the magnetization of the two superconductors is parallel and suppressed in the anti-parallel case. We also analyze the noise spectrum that shows signatures of the ground-state transition in the form of an elevated zero-frequency noise.
超导性和磁性是相互竞争的效应，在某些情况下可以共存。它们的共存会导致意想不到的新行为，包括奇异电子对机制的出现和拓扑相。在这项工作中，我们研究了两个自旋分裂超导体之间约瑟夫森结的性质。超导体中的自旋分裂可以由与铁磁材料的耦合或外部磁场引起。结的性质由同样分裂的安德列夫束缚态主导。这些态之一可以穿过超导体的费米能级，导致以超电流抑制为特征的基态转变。我们将超电流阻塞解释为来自结附近p波配对的主导，此时电子在两侧。为了支持这一解释，我们分析了不同的配对通道，并表明在两个超导体的磁化平行的情况下p波配对占优，而在反平行情况下受到抑制。我们还分析了噪声谱，它以升高的零频噪声的形式显示了基态转变的特征。
