Majorana zero modes in impurity-assisted vortex of LiFeAs superconductor

• Published in: Nature communications Vol. 12; no. 1; p. 4146
• Main Authors: Kong, Lingyuan, Cao, Lu, Zhu, Shiyu, Papaj, Michał, Dai, Guangyang, Li, Geng, Fan, Peng, Liu, Wenyao, Yang, Fazhi, Wang, Xiancheng, Du, Shixuan, Jin, Changqing, Fu, Liang, Gao, Hong-Jun, Ding, Hong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06-07-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 147/138; 639/766/119/1003; 639/766/119/2792/4128; Braiding; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Elementary excitations; Fermions; Humanities and Social Sciences; Impurities; Inhomogeneity; Iron; MATERIALS SCIENCE; multidisciplinary; Quantum computing; Qubits (quantum computing); Scanning tunneling microscopy; Science; Science (multidisciplinary); Superconductors; Topology; Tuning; Vortices
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24372-6

The iron-based superconductor is emerging as a promising platform for Majorana zero mode, which can be used to implement topological quantum computation. One of the most significant advances of this platform is the appearance of large vortex level spacing that strongly protects Majorana zero mode from other low-lying quasiparticles. Despite the advantages in the context of physics research, the inhomogeneity of various aspects hampers the practical construction of topological qubits in the compounds studied so far. Here we show that the stoichiometric superconductor LiFeAs is a good candidate to overcome this obstacle. By using scanning tunneling microscopy, we discover that the Majorana zero modes, which are absent on the natural clean surface, can appear in vortices influenced by native impurities. Our detailed analysis reveals a new mechanism for the emergence of those Majorana zero modes, i.e. native tuning of bulk Dirac fermions. The discovery of Majorana zero modes in this homogeneous material, with a promise of tunability, offers an ideal material platform for manipulating and braiding Majorana zero modes, pushing one step forward towards topological quantum computation.
Despite the discovery of Majorana zero modes (MZM) in iron-based superconductors, sample inhomogeneity may destroy MZMs during braiding. Here, authors observe MZM in impurity-assisted vortices due to tuning of the bulk Dirac fermions in a homogeneous superconductor LiFeAs.