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►【拓扑量子计算卓越中心-KITS-IOP 联合报告】

Title: Observation of large-scale, highly-ordered and tunable Majorana zero mode lattice in LiFeAs

Speaker: Prof. Geng Li, Prof. Hongjun Gao, IOP;

Time: June 24 (Friday), 15:00

Place: M236, IOP M-building; Online

Abstract:

Majorana zero modes (MZMs) obey non-Abelian statistics and are considered building blocks for constructing topological qubits. Iron-based superconductors with topological band structures have emerged as promising hosting materials, since isolated candidate MZMs in the quantum limit have been observed inside the topological vortex cores. However, these materials suffer from issues related to alloying-induced disorder, uncontrolled vortex lattices and a low yield of topological vortices, hindering their potential applications. I would like to talk about our recent observation of the formation of an ordered and tunable MZM lattice in naturally-strained stoichiometric LiFeAs. Strain in the crystal produces biaxial charge density wave stripes along the Fe-Fe and As-As directions. The charge density wave in the As-As direction strongly modulates the superconductivity, and the vortices are hence pinned exclusively on the As-As charge density wave stripes, forming an ordered lattice. More than 90 percent of the vortices are topological and possess the characteristics of isolated MZMs at the vortex center, forming an ordered MZM lattice with the density and the geometry tunable by an external magnetic field. Remarkably, with decreasing the spacing of neighboring vortices, the MZMs start to couple with each other. These findings provide a new pathway towards tunable and ordered MZM lattices as a platform for future topological quantum computation.

Reference:

1. Li, M. et al., Nature, doi.org/10.1038/s41586-022-04744-8 (2022)

2. Kong, L. Y. et al., Nat. Commun., 12, 4146 (2021)

3. Cao, L. et al., Nat. Commun., 12, 6312 (2021)

4. Yim, C. M. et al., Nat. Commun., 9, 2602 (2018)