Statistical learning of engineered topological phases in the kagome superlattice of AV$_3$Sb$_5$

TL;DR

This paper uses a statistical approach to explore and predict various topological phases, including higher-order ones, in kagome superlattices of AV$_3$Sb$_5$, linking theoretical models with experimental observations.

Contribution

It introduces a statistical method to identify and analyze topological phases in kagome lattices, revealing potential new phases and real-space signatures.

Findings

Identification of possible topological phases in kagome superlattices

Prediction of new higher-order topological phases

Correlation of theoretical models with experimental signatures

Abstract

Recent experimental findings have reported the presence of unconventional charge orders in the enlarged ($2 \times 2$) unit-cell of kagome metals AV$_3$Sb$_5$ (A=K,Rb,Cs) and hinted towards specific topological signatures. Motivated by these discoveries, we investigate the types of topological phases that can be realized in such kagome superlattices. In this context, we employ a recently introduced statistical method capable of constructing topological models for any generic lattice. By analyzing large data sets generated from symmetry-guided distributions of randomized tight-binding parameters, and labeled with the corresponding topological index, we extract physically meaningful information. We illustrate the possible real-space manifestations of charge and bond modulations and associated flux patterns for different topological classes, and discuss their relation to present theoretical predictions and experimental signatures for the AV$_3$Sb$_5$ family. Simultaneously, we predict new higher-order topological phases that may be realized by appropriately manipulating the currently known systems.