AI 中文总结
该研究制备分子Haldane链，发现其自旋-1/2边缘态与超导体的耦合呈宇称依赖，奇长链形成特定束缚态、偶长链解耦，为分子自旋量子比特提供新路径。
AI 中文摘要
拓扑序可使基础粒子的量子数分数化，典型例子是反铁磁整数自旋链边缘的自旋-1/2态，受体内拓扑Haldane能隙保护，且在短链中相互耦合。由于其拓扑保护特性，这些态是混合自旋-超导体量子系统的天然构建模块。然而，分数化是否能在与超导凝聚体耦合后保留仍是开放问题。本研究在近邻化Au(111)/Nb(110)表面生长反铁磁耦合自旋-1三亚苯单元构成的分子Haldane链，通过扫描隧道谱解析其自旋-1/2边缘态与超导凝聚体的宇称依赖耦合：奇长链因净S=1基态在超导能隙内形成Yu-Shiba-Rusinov束缚态，偶长链则形成与超导体解耦的S=0基态。双位点超导体模型表明，这种交替源于边缘间相互作用的符号与强度，隧穿谱中超导能隙外的自旋激发验证了该机制；还检测到因Haldane能隙大得多而与超导体解耦的集体多体自旋激发模式。边缘自旋与超导体的长度可调耦合为基于π共轭碳结构的分子自旋量子比特开辟了途径。
英文摘要
Topological order can fractionalize the quantum numbers of the underlying particles. A paradigmatic example is the spin-1/2 states at the edges of an antiferromagnetic integer-spin chain, protected by a topological Haldane gap in the bulk and mutually coupled in short chains. Owing to their topological protection, they are natural building blocks for hybrid spin-superconductor quantum systems. Whether fractionalization survives the coupling to a superconducting condensate, however, remains an open question. Here we grow molecular Haldane chains of antiferromagnetically coupled spin-1 triangulene units on a proximitized Au(111)/Nb(110) surface and resolve a parity-dependent coupling of their spin-1/2 edge states to the superconducting condensate by scanning tunnelling spectroscopy. Odd-length chains host Yu-Shiba-Rusinov bound states inside the superconducting gap, originating from the net S=1 ground state, whereas even-length chains form an S=0 ground state decoupled from the superconductor. A two-site superconductor model reveals that this alternation arises from the sign and strength of the inter-edge interaction, a mechanism independently validated by extra-gap spin excitations in tunnelling spectra. Collective many-body spin excitation modes are also detected decoupled from the superconductor by the much larger Haldane gap. The length-tunable coupling of the edge spins to the superconductor opens a route toward molecular spin qubits based on $π$-conjugated carbon architectures.
Comments12 pages, 4 figures, Supplementary Information included
