A simple method to construct Flat Band lattices

TL;DR

This paper presents a straightforward, general approach for constructing flat band lattices with customizable degenerate localized states, applicable to various dimensions and tested through numerical simulations.

Contribution

It introduces a simple, universal method to build flat band lattices by repeating mini-arrays, enabling control over degenerate states and flat band formation.

Findings

Successfully constructs flat band lattices in 1D and 2D.

Demonstrates the method's effectiveness through numerical examples.

Analyzes the impact of interactions like anisotropy and nonlinearity.

Abstract

We develop a simple and general method to construct arbitrary Flat Band lattices. We identify the basic ingredients behind zero-dispersion bands and develop a method to construct extended lattices based on a consecutive repetition of a given mini-array. The number of degenerated localized states is defined by the number of connected mini-arrays times the number of modes preserving the symmetry at a given connector site. In this way, we create one or more (depending on the lattice geometry) complete degenerated Flat Bands for quasi-one and two-dimensional systems. We probe our method by studying several examples, and discuss the effect of additional interactions like anisotropy or nonlinearity. At the end, we test our method by studying numerically a ribbon lattice using a continuous description.