Three-dimensional deformations in single-layer $\alpha$ antimonene and interaction with a Au(111) surface from first principles

TL;DR

This study uses density functional theory to analyze the electronic structure and deformation of alpha antimonene monolayers, revealing strain-induced bandgap opening and strong substrate interactions with gold that alter electronic properties.

Contribution

It provides new insights into the puckering stability, strain effects, and substrate interactions of alpha antimonene from first principles, challenging previous assumptions.

Findings

Isolated alpha antimonene has a modulated puckering, not uniform.

Strain induces a double-cone electronic feature with a 21 meV bandgap.

Gold substrate causes strong hybridization and modifies electronic structure.

Abstract

Using density functional theory, we investigate the electronic structure of the alpha phase of an antimony monolayer in its isolated form and in contact to the (111) surface of gold. We demonstrate that the isolated single-layer actually displays a slightly modulated puckering that stabilizes the monolayer, not a uniform one as often assumed. Moreover, it has dramatic consequences on the electronic band structure: the material is a semiconductor with low-dispersing bands near the Brillouin zone center. By further application of about 12% strain on the armchair direction, a double-cone features develops wherein an electronic bandgap of about 21~meV is found. When in contact with a Au(111) surface, a strong interaction with gold arises, as it appears clearly from (i) substantial atomic displacements compared to the isolated form, and (ii) hybridization of Sb and Au orbitals. The latter profoundly modifies the electronic band structure by strengthening the spin-orbit splitting of hybridized bands and spoiling the double-cone feature whose manipulation through substrate-induced strain appears therefore questionable, at least in the simulated epitaxial implementation.