Matter Waves in Atomic Artificial Graphene

TL;DR

This paper introduces a model for creating artificial graphene using cold atoms in a 2D optical lattice, analyzing its band structure, Dirac cones, and flat bands with tunable interactions.

Contribution

It provides an exact Green function approach to study matter wave scattering in an atomic artificial graphene system with tunable inter-species interactions.

Findings

Dirac cones emerge in the band structure.

Multiple energy gaps appear with varying interactions.

A flat, non-dispersive band is observed.

Abstract

We present a new model to realize artificial 2D lattices with cold atoms investigating the atomic artificial graphene: a 2D-confined matter wave is scattered by atoms of a second species trapped around the nodes of a honeycomb optical lattice. The system allows an exact determination of the Green function, hence of the transport properties. The inter-species interaction can be tuned via the interplay between scattering length and confinements. Band structure and density of states of a periodic lattice are derived for different values of the interaction strength. Emergence and features of Dirac cones are pointed out, together with the appearance of multiple gaps and a non-dispersive and isolated flat band. Robustness against finite-size and vacancies effects is numerically investigated.