Ho-Pb Monolayers With Kagome and Striped Structures

Scaling the electronic and magnetic phases to the monolayer limit is able to produce a rich and complex landscape of emergent effects, highly promising for applications in ultracompact spintronic devices. Here, we report on the epitaxial synthesis of a two-dimensional Pb-based kagome monolayer ${\mathrm{HoPb}}_3$ and suggest a strategy to engineer the periodic structure with alternating ${\mathrm{HoPb}}_3$ and Pb stripes. Both phases demonstrate a Rashba-like spin polarization and several Van Hove singularities in the band structure, including high-order ones, which potentially may enable the strong electronic correlations. The DFT calculations have predicted that both 2D and quasi-1D phases exhibit an unusual combination of in-plane noncollinear antiferromagnetic alignment of Ho magnetic moments, along with small out-of-plane spin polarization, which makes them ferrimagnets. Furthermore, the striped phase was found to hold the fingerprints of the 1D Tomonaga-Luttinger liquid. Our results offer a versatile approach to control the anisotropy of low-dimensional materials, facilitating the development of tunable spintronic devices.