Progress on artificial flat band systems: classifying, perturbing, applying

TL;DR

This paper reviews recent advances in artificial flat band systems, focusing on classification, perturbation effects, and experimental realizations, highlighting progress in understanding and engineering flat band phenomena.

Contribution

It provides a comprehensive overview of flat band classification, perturbation analysis, and experimental implementations, synthesizing recent developments in the field.

Findings

Development of flat band generators based on compact localized states

Insights into disorder effects and many-body interactions in flat bands

Compilation of diverse experimental realizations of flat band systems

Abstract

We highlight recent progress in the study of artificial flat band systems with a threefold focus. First, we discuss single-particle flat band physics, which has advanced through the design of various flat band generators. These generators rely on the classification of flat bands in terms of compact localized states - their fundamental building blocks. A related development is the complete real-space description of flat band projectors. Next, we review studies on perturbations of flat bands, which provide new insights into the effects of disorder and, more importantly, the intricate interplay between many-body interactions and flat band physics. Finally, we survey the growing number of experimental realizations of flat bands across diverse physical platforms.