Structural investigation of pristine and Mn-intercalated flat-honeycomb bismuthene on Ag(111)

Honeycomb bismuthene structures on Ag(111) were investigated using low-energy electron diffraction (LEED) and density functional theory. LEED I(V) analysis revealed that 0.5 monolayer (ML) of Bi forms an ultraflat honeycomb lattice with negligible buckling at ~120 K, which transforms into other structures upon warming to room temperature. A similar flat bismuthene structure also forms in Mn/Bi/Ag(111), which remains stable even at room temperature. Mn deposition on $(p\times \sqrt{3})$-rect Bi/Ag(111) induces Bi surface segregation, as confirmed by X-ray photoelectron spectroscopy, resulting in a p$(2\times2)$ honeycomb bismuthene. The detailed structural investigation provides fundamental insights into the characterization of two-dimensional topological properties of bismuthene grown on Ag(111).