Band structure of silicene on the zirconium diboride (0001) thin film surface - convergence of experiment and calculations in the one-Si-atom Brillouin zone

TL;DR

This study reconciles experimental ARPES spectra with first-principles calculations for silicene on ZrB₂(0001), revealing the importance of Brillouin zone representation and lattice variation in understanding its electronic structure.

Contribution

It demonstrates that representing silicene's band structure in a large Brillouin zone with a single Si atom aligns calculations with experimental spectra, resolving previous controversies.

Findings

Convergence of DFT calculations and ARPES data in a wide energy range.

Identification of the 'planar-like' phase as the electronic ground state.

Orbital character analysis of states near the Fermi level.

Abstract

So far, it represents a challenging task to reproduce angle-resolved photoelectron (ARPES) spectra of epitaxial silicene by first-principles calculations. Here, we report on the resolution of the previously controversial issue related to the structural configuration of silicene on the ZrB$_2$(0001) surface and its band structure. In particular, by representing the band structure in a large Brillouin zone associated with a single Si atom, it is found that the imaginary part of the one-particle Green's function follows the spectral weight observed in ARPES spectra. By additionally varying the in-plane lattice constant, the results of density functional theory calculations and ARPES data obtained in a wide energy range converge into the "planar-like" phase and provide the orbital character of electronic states in the vicinity of the Fermi level. It is anticipated that the choice of a smaller commensurate unit cell for the representation of the electronic structure will be useful for the study of epitaxial two-dimensional materials on various substrates in general.