| Title | End states and subgap structure in proximity-coupled chains of magnetic adatoms |
| Authors | M. Ruby, F. Pientka, Y. Peng, F. von Oppen, B. W. Heinrich, K. J. Franke |
| Journal | Phys. Rev. Lett. |
| Vol. 115, 2015, pg. 197204 |
| Abstract | A recent experiment [Nadj-Perge et al., Science 346, 602 (2014)] provides evidence for Majorana zero modes in iron (Fe) chains on the superconducting Pb(110) surface. Here, we study this system by scanning tunneling microscopy using superconducting tips. This high-resolution technique resolves a rich subgap structure, including zero-energy excitations in some chains. We compare the symmetry properties of the data under voltage reversal against theoretical expectations and provide evidence that the putative Majorana signature overlaps with a previously unresolved ow-energy resonance. Interpreting the data within a Majorana framework suggests that the topological gap is significantly smaller than previously believed. Aided by model calculations, we also analyze higher energy features of the subgap spectrum and their relation to high-bias peaks which we associate with the Fe d-bands. |
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