Self-Intercalated 1T-FeSe2 as an Effective Kagome Lattice

In kagome lattice, with the emergence of Dirac cones and flat band in electronic structure, it provides a versatile ground for exploring intriguing interplay among frustrated geometry, topology and correlation. However, such engaging interest is strongly limited by available kagome materials in nature. Here we report on a synthetic strategy of constructing kagome systems via self-intercalation of Fe atoms into the van der Waals gap of FeSe2 via molecular beam epitaxy. Using low-temperature scanning tunneling microscopy, we unveil a kagome-like morphology upon intercalating a 2 x 2 ordered Fe atoms, resulting in a stoichiometry of Fe5Se8. Both the bias-dependent STM imaging and theoretical modeling calculations suggest that the kagome pattern mainly originates from slight but important reconstruction of topmost Se atoms, incurred by the nonequivalent subsurface Fe sites due to the intercalation. Our study demonstrates an alternative approach of constructing artificial kagome structures, which envisions to be tuned for exploring correlated quantum states.

Automated summary

By self-intercalating Fe atoms into the van der Waals gap of FeSe2 using molecular beam epitaxy, we successfully constructed kagome-like structures. The resulting Fe5Se8 stoichiometry was observed using low-temperature scanning tunneling microscopy, showing the emergence of a 2 x 2 ordered Fe atom arrangement. The kagome pattern mainly originates from the slight reconstruction of topmost Se atoms due to the non-equivalent subsurface Fe sites caused by intercalation. This study presents an alternative approach for constructing artificial kagome structures, opening up possibilities for exploring correlated quantum states.