Engineering Quantum Wonders on Kagome Weyl Semimetal Surfaces

The kagome-lattice magnetic Weyl semimetal Co3Sn2S2 has emerged as a versatile platform for exploring the interplays among band topology, magnetism, and electron correlations. Its unique properties hold potentials for next-generation electronic and spintronic applications. Recent research has provided an overview of advances in understanding its surface atomic and electronic structures and discovering novel physical properties.

A foundational step in this exploration involved synthesizing ultra-high quality Co3Sn2S2 single crystals using an iterative chemical vapor transport growth methodology. This technique enables the growth of large, stoichiometric crystals with significantly enhanced physical properties. With these high-quality crystals, researchers employed a suite of advanced techniques, including joint work function measurements, bond-resolved non-contact atomic force microscopy, short-range force spectroscopy, and density functional theory calculations, to elucidate atomic scale identification of cleaved surfaces. Based on the explicitly identified surface, the research highlighted the discovery and manipulation of localized spin-orbit polarons (SOPs) at S vacancies on the S surface, emphasizing their electronic and magnetic properties and the ability of manipulating specific SOP configurations at the atomic scale.

Beyond SOPs, the research further showed oxygen-induced quantum clusters, where O dopants modify the electronic states of surrounding atoms. These clusters provide building blocks for scalable functional quantum structures. Additionally, the discovery of kagome electronic states on the Sn-terminated triangular-lattice surface was presented, along with an outlined strategy for constructing such states with tunable properties.

As lead author Huang notes in the paper, "Collectively, these developments illustrate how high-quality crystal growth, atomic-scale imaging and manipulation, and defect/dopant engineering can be effectively integrated to discover and manipulate emergent novel physical properties of a kagome Weyl semimetal, opening new avenues for atomically precise design and surface state engineering in quantum materials."