2025/04/09 by Ikegaya, Satoshi, Kobayashi, Shingo, Asano, Yasuhiro
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2504.06524
We study finite-size-induced topological phenomena in unconventional superconductors. Specifically, we focus on a thin film with a persistent spin texture, fabricated on a high-Tc cuprate dxy-wave superconductors. In two-dimensional dxy-wave superconductors, flat-band Andreev bound states appear at the edges. As the system narrows, these bound states acquire an energy gap due to finite-size hybridization and spin-orbit coupling of the persistent spin texture. This induced gap gives rise to the emergence of a topological phase, characterized by an exceptionally large one-dimensional winding number that scales with the film width. We demonstrate the appearance of highly degenerate zero-energy states, leading to anomalous perfect charge transport in dirty superconducting junctions. These findings provide a promising platform for exploring fascinating topological superconducting phases driven by gapped Andreev bound states.