Electrostatic quantum dots in silicene

TL;DR

This paper investigates electrostatic quantum dot confinement in silicene using atomistic and continuum models, demonstrating localized states that are decoupled from edges and unaffected by crystal termination.

Contribution

It introduces a method for electrostatic quantum dot confinement in silicene and analyzes the resulting localized states with atomistic and continuum approaches.

Findings

Localized states are confined within the quantum dot.

Localized states are decoupled from the edge effects.

Electrostatic confinement reduces intervalley scattering in armchair edges.

Abstract

We study electrostatic quantum dot confinement for charge carriers in silicene. The confinement is formed by vertical electric field surrounding the quantum dot area. The resulting energy gap in the outside of the quantum dot traps the carriers within, and the difference of electrostatic potentials on the buckled silicene sublattices produces nonzero carrier masses outside the quantum dot. We study the electrostatic confinement defined inside a silicene flake with both the atomistic tight-binding approach as well as with the continuum approximation for a circularly symmetric electrostatic potential. We find localization of the states within the quantum dot and their decoupling from the edge that makes the spectrum of the localized states independent of the crystal termination. For an armchair edge of the flake removal of the intervalley scattering by the electrostatic confinement is found