Kagome on beta-Sb with valley-hot Berry curvature and tunable intrinsic SHC

Abstract

Large-area, single-crystalline antimonene polygonal domains self-assemble on Al(111) at room temperature without forming an interfacial alloy layer by MBE. Beyond the beta-Sb phase,with increasing deposition, once the beta-Sb coverage surpasses a threshold, we observe a previously unreported kagome-Sb overlayer. STM height maps and line profiles track a phase evolution from an enlarged-period honeycomb to a close-packed layer and ultimately a kagome lattice. XPS peak not only shows resolves a time-dependent redistribution of Sb-related components that quantitatively mirrors the STM-observed phase sequence, but also revals the substrate core levels remain unchanged, ruling out interfacial alloying throughout growth. ARPES of beta-Sb resolves a Dirac-like crossing at Gamma around -1.4 eV, in agreement with first-principles calculations. Although beta-Sb is Z2-trivial and the heterostructure is metallic, Wannier-based calculations reveal valley-contrasting Berry-curvature hotspots, yielding an intrinsic spin Hall conductivity that is strongly Fermi-level dependent. These results demonstrate a reproducible kagome-Sb/beta-Sb heterophase interface and uncover a controllable spin-orbit-driven response in a homoelemental 2D system.