تصوير الدوامات التلقائية في مركب نانوي فائق التوصيل غير منتظم ✛

الملخص الأصلي

كما كتبه المؤلفون، بالإنجليزية arXiv:2607.14697

Observation of spontaneous symmetry breaking is crucial to our understanding of a continuous second-order phase transition from a disordered system into an ordered one, which often leads to the formation of topological defects. In the case of superconductors, such topological defects are identified as quantized vortices. However, their geometrical characteristics have not been well investigated and understood yet. For the imaging of spontaneous vortices, we employ a proximity-coupled superconducting nanocomposite. Here we show from scanning superconducting quantum interference device microscope measurements that vortices with different polarities, size and shapes are observed stochastically especially under near zero-field conditions. The field distributions of the spontaneous vortices are more extended and intricate than those of the field induced Abrikosov vortices, yielding longer penetration depths ranging from ~1 to ~10 micrometer. The spontaneous vortices are created during cooling as a result of the competition between Josephson coupling and thermal phase fluctuation, both of which are inherently present in this proximity-coupled system. The morphology of the vortices most likely imprints the information that is frozen at the time of vortex formation, providing insights into the local phase differences that are present in the early stage of the phase transition.