Surface reconstruction-driven band folding and spin-orbit enhancement at the $\alpha$-antimonene/Au(111) interface

TL;DR

This study explores how the substrate influences the electronic properties of 2D α-antimonene, revealing band folding, hybridization effects, and enhanced spin-orbit interactions at the interface with Au(111).

Contribution

It demonstrates substrate-induced modifications in α-antimonene's electronic structure, including band folding and spin-orbit enhancement, using combined experimental and theoretical approaches.

Findings

Strong hybridization at Sb/Au interface causes band folding.

Substrate effects can overshadow pristine antimonene properties.

Spin-orbit splitting is significantly enhanced by substrate hybridization.

Abstract

The electronic properties of the two-dimensional (2D) $\alpha$ phase of antimonene are unique, featuring unpinned Dirac cones that can be moved with strain. Here we investigate the structural and electronic properties of an epitaxial 2D $\alpha$-antimonene, grown on Au(111). Using angle-resolved photoemission spectroscopy and density-functional theory, we reveal a strong hybridization at the Sb/Au interface, which imprints a rectangular reconstruction in the Au states, producing a band folding and hybrid bands exhibiting trigonal pockets. Additionally, hybridization displaces part of the Au wavefunction in regions of large electrostatic potential gradient, thereby enhancing spin-orbit splitting. Our work underscores that the pristine electronic properties of $\alpha$-antimonene may be deeply modified by its substrate, and even overwhelmed by the bands of the latter, and also shows that spin-orbit interaction in a heavy metal (Au) can be substantially enhanced by a lighter element (Sb).