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

TL;DR

This study reports the formation of a kagome-Sb overlayer on beta-Sb, revealing a phase evolution, electronic properties with valley-contrasting Berry curvature, and tunable intrinsic spin Hall conductivity in a homoelemental 2D system.

Contribution

It uncovers a reproducible kagome-Sb/beta-Sb heterophase interface and demonstrates a controllable spin-orbit-driven response in a homoelemental 2D material.

Findings

Kagome-Sb overlayer forms after beta-Sb exceeds a threshold coverage.

Valley-contrasting Berry curvature hotspots are identified in beta-Sb.

Intrinsic spin Hall conductivity is strongly Fermi-level dependent.

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.