Chains of magnetic atoms with either strong spin-orbit coupling or spiral magnetic order which are proximity-coupled to superconducting substrates can host topologically non-trivial Majorana bound states. The experimental signature of these states consists of spectral weight at the Fermi energy which is spatially localized near the ends of the chain. However, topologically trivial Yu-Shiba-Rusinov in-gap states localized near the ends of the chain can lead to similar spectra. Here, we explore a protocol to disentangle these contributions by artificially augmenting a candidate Majorana spin chain with orbitally-compatible nonmagnetic atoms. Combining scanning tunneling spectroscopy with ab-initio and tight-binding calculations, we realize a sharp spatial transition between the proximity-coupled spiral magnetic order and the non-magnetic superconducting wire termination, with persistent zero-energy spectral weight localized at either end of the magnetic spiral. Our findings open a new path towards the control of the spatial position of in-gap end states, trivial or Majorana, via different chain terminations, and the realization of designer Majorana chain networks for demonstrating topological quantum computation.

具有强自旋轨道耦合或螺旋磁序的磁性原子链与超导衬底接近耦合，可以承载拓扑上非平凡的马约拉纳束缚态。这些状态的实验特征由费米能量处的光谱权重组成，该能量在空间上位于链末端附近。然而，位于链末端附近的拓扑微不足道的 Yu-Shiba-Rusinov 带隙状态可以导致类似的光谱。在这里，我们探索了一种协议，通过用轨道兼容的非磁性原子人为地增加候选马约拉纳自旋链来解开这些贡献。将扫描隧道光谱与 ab-initio 和紧束缚计算相结合，我们实现了邻近耦合螺旋磁序和非磁性超导线端之间的急剧空间过渡，在磁螺旋的任一端都具有持续的零能谱权重。我们的发现开辟了一条通过不同链终止控制带隙终态（平凡或马约拉纳）空间位置的新途径，并实现了设计者马约拉纳链网络以演示拓扑量子计算。