Atomically\nThin Two-Dimensional Kagome Flat Band on\nthe Silicon Surface

In\ncondensed matter physics, the Kagome lattice and its inherent\nflat bands have attracted considerable attention for their prediction\nand observation to host a variety of exotic physical phenomena. Despite\nextensive efforts to fabricate thin films of Kagome materials aimed\nat modulating flat bands through electrostatic gating or strain manipulation,\nprogress has been limited. Here, we report the observation of a d-orbital\nhybridized Kagome-derived flat band in Ag/Si(111) 3×3 as revealed by angle-resolved photoemission\nspectroscopy. Our findings indicate that silver atoms on a silicon\nsubstrate form an unconventional distorted breathing Kagome structure,\nwhere a delicate balance in the hopping parameters of the in-plane\nd-orbitals leads to destructive interference, resulting in double\nflat bands. The exact quantum destructive interference mechanism that\nforms the flat band is uncovered in a rigorous manner that has not\nbeen described before. These results illuminate the potential for\nintegrating metal–semiconductor interfaces on semiconductor\nsurfaces into Kagome physics, particularly in exploring the flat bands\nof ideal 2D Kagome systems.