Does the Dirac Cone Exist in Silicene on Metal Substrates?

TL;DR

This study investigates the presence of Dirac cones in silicene on various metal substrates and demonstrates that intercalating alkali metals can restore the Dirac cone, enabling further exploration of silicene's properties.

Contribution

It reveals the common absence of Dirac cones in silicene on metals and proposes a method to restore them via alkali metal intercalation.

Findings

Dirac cones are absent in silicene on several metal substrates due to band hybridization.

Intercalation of alkali metals restores the Dirac cone with linear or parabolic dispersion.

Restored Dirac cones allow study of silicene's properties without transferring from substrates.

Abstract

Absence of the Dirac cone due to a strong band hybridization is revealed to be a common feature for epitaxial silicene on metal substrates according to our first-principles calculations for silicene on Ir, Cu, Mg, Au, Pt, Al, and Ag substrates. The destroyed Dirac cone of silicene, however, can be effectively restored with linear or parabolic dispersion by intercalating alkali metal atoms between silicene and the metal substrates, offering an opportunity to study the intriguing properties of silicene without further transfer of silicene from the metal substrates.