The Effective Model of the Molecule Graphene System and One Application Beyond Graphene

TL;DR

This paper analyzes the effective models of molecule graphene, estimates parameters for Cu/CO systems, and demonstrates how to design molecule lattices to realize various 2D electron lattices like Kagome, enabling experimental testing of their properties.

Contribution

It provides a method to map molecule arrangements to desired 2D electron lattices and designs a Kagome lattice using molecule graphene techniques.

Findings

Estimated model parameters for Cu/CO system.

Designed a molecule lattice to realize Kagome-like lattice.

Calculated energy bands and LDOS for the designed lattice.

Abstract

Recently, a new kind of two dimensional (2D) artificial electron lattice, i.e. molecule graphene, has drawn a lots of interest, where the metal surface electrons are transformed into a honeycomb lattice via absorbing a molecule lattice on metal surface. In this work, we would like to point out that the technique used to build molecule graphene actually gives a promising way to explore the interesting physics of other novel 2D lattice beyond graphene. The key issue is that this system is an antidot system, where the absorbed molecule normally gives a repulsive potential. So, we need to establish a map between the molecule arrangement and the desired surface electron lattice. To give a concrete example, we first analyse the effective models of molecule graphene, and estimate the model parameters for the Cu/CO system through numerical fitting the exerimental data. Then, we design a molecule lattice, and show that, with this kind of lattice, the surface electrons can be transformed into a Kagome like lattice. Using the estimated parameters of Cu/CO system, we calculate the corresponding energy bands and LDOS, which can be readily tested in experiment. We hope that our work can stimulate further theoretical and experimental interest in this novel artificial 2D electron lattice.