Observation of Majorana fermions in ferromagnetic atomic chains on a superconductor

By S. Nadj-Perge, I. Drozdov, Jian Li, Hua Chen, Sangjun Jeon, Jungpil Seo, Allan H. MacDonald, Bogdan Andrei Bernevig, A. Yazdani. Science, 2014

1,714 citations recorded by the source corpus.

A possible sighting of Majorana states Nearly 80 years ago, the Italian physicist Ettore Majorana proposed the existence of an unusual type of particle that is its own antiparticle, the so-called Majorana fermion. The search for a free Majorana fermion has so far been unsuccessful, but bound Majorana-like collective excitations may exist in certain exotic superconductors. Nadj-Perge et al. created such a topological superconductor by depositing iron atoms onto the surface of superconducting lead, forming atomic chains (see the Perspective by Lee). They then used a scanning tunneling microscope to observe enhanced conductance at the ends of these chains at zero energy, where theory predicts Majorana states should appear. Science, this issue p. 602; see also p. 547 Scanning tunneling microscopy is used to observe signatures of Majorana states at the ends of iron atom chains. [Also see Perspective by Lee] Majorana fermions are predicted to localize at the edge of a topological superconductor, a state of matter that can form when a ferromagnetic system is placed in proximity to a conventional superconductor with strong spin-orbit interaction. With the goal of realizing a one-dimensional topological superconductor, we have fabricated ferromagnetic iron (Fe) atomic chains on the surface of superconducting lead (Pb). Using high-resolution spectroscopic imaging techniques, we show that the onset of superconductivity, which gaps the electronic density of states in the bulk of the Fe chains, is accompanied by the appearance of zero-energy end-states. This spatially resolved signature provides strong evidence, corroborated by other observations, for the formation of a topological phase and edge-bound Majorana fermions in our atomic chains.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/a4e44c98eacff60cc36669fac620974e05d7ec50

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. Y. Ando
2. Masatoshi Sato
3. J. Alicea
4. Hsin Lin
5. Arun Bansil
6. Tanmoy Das
7. Ashvin Vishwanath
8. X. Dai

In Condensed Matter Physics

1. Y. Ando
2. Masatoshi Sato
3. J. Linder
4. J. Alicea
5. H. Weng
6. B. Nijholt
7. X. Dai
8. Z. Fang

Citations in the corpus

• Engineered platforms for topological superconductivity and Majorana zero modes (2021, background): “Panel a reprinted with permission from ref.(92), AAAS.”
• New perspectives for Rashba spin-orbit coupling. (2015, background): “Another recent experiment has attempted to look for Majorana fermions in chains of magnetic atoms on a superconductor surface [99].”
• Milestones toward Majorana-based quantum computing (2015, background): “For instance, with only straightforward modifications, fusion-rule detection and topological qubit validation experiments should be adaptable to transmon-based devices; other setups, such as ferromagnetic atomic chains on superconductors [16,23], may require more dramatic modifications and thus pose”
• Colloquium : Topological band theory (2016, background): “(Pientka, Glazman, and von Oppen 2013; Heimes, Kotetes, and Schön 2014) Such bond states have been reported by STM in Fe chains on superconducting Pb.(Nadj-Perge et al. 2014)”
• Materials challenges and opportunities for quantum computing hardware (2021, background): “The pursuit of non-Abelian MZMs in topological superconductors has involved measurements of a rich variety of materials, including vortices at topological insulator/superconductor heterointerfaces such as Bi2Se3/NbSe2 (327, 328), magnetic topological insulator/superconductor devices such as Cr-doped”
• Colloquium : Quantum anomalous Hall effect (2022, background): “…heterostructures During the past decades, the search for Majorana modes has been a key activity of condensed matter physics(Das et al., 2012; Deng et al., 2012; Jeon et al., 2017; Kayyalha et al., 2020; Mourik et al., 2012; Nadj-Perge et al., 2014; Rokhinson et al., 2012; Wang et al., 2018a).”