Probing Atomic Structure and Majorana Wavefunctions in Mono-Atomic Fe-chains on Superconducting Pb-Surface

TL;DR

This study combines STM and AFM to investigate mono-atomic Fe chains on Pb surface, revealing localized Majorana bound states at chain ends, supporting their potential use in quantum computing.

Contribution

It provides direct spatial and electronic evidence of Majorana bound states in mono-atomic Fe chains on superconducting Pb, demonstrating their localization and potential for qubit implementation.

Findings

Majorana bound states are localized at chain ends below 25 nm.

Fe chains are mono-atomic and linear.

Zero-bias conductance peaks indicate MBS presence.

Abstract

Motivated by the striking promise of quantum computation, Majorana bound states (MBSs) in solid-state systems have attracted wide attention in recent years. In particular, the wavefunction localization of MBSs is a key feature and crucial for their future implementation as qubits. Here, we investigate the spatial and electronic characteristics of topological superconducting chains of iron atoms on the surface of Pb(110) by combining scanning tunneling microscopy (STM) and atomic force microscopy (AFM). We demonstrate that the Fe chains are mono-atomic, structured in a linear fashion, and exhibit zero-bias conductance peaks at their ends which we interprete as signature for a Majorana bound state. Spatially resolved conductance maps of the atomic chains reveal that the MBSs are well localized at the chain ends (below 25 nm), with two localization lengths as predicted by theory. Our observation lends strong support to use MBSs in Fe chains as qubits for quantum computing devices.