Low-energy effective theory and symmetry classification of flux phases on Kagome lattice

TL;DR

This paper develops a low-energy effective theory for flux phases on Kagome lattices, classifies all possible flux phases, and explores their relation to symmetry breaking and time-reversal symmetry breaking phenomena.

Contribution

It provides a comprehensive classification of 183 flux phases on Kagome lattices using symmetry analysis and brute-force enumeration, advancing understanding of flux phases in correlated materials.

Findings

Identified 183 flux phases within 2x2 unit cell

Classified flux phases by point group symmetry

Connected flux phases to time-reversal symmetry breaking phenomena

Abstract

Motivated by recent experiments on AV$_3$Sb$_5$ (A=K,Rb,Cs), the chiral flux phase has been proposed to explain time-reversal symmetry breaking. To fully understand the physics behind the chiral flux phase, we construct a low-energy effective theory based on the van-Hove points around the Fermi surface. The possible symmetry-breaking states and their classifications of the low-energy effective theory are completely studied, especially the flux phases on Kagome lattice. In addition, we discuss the relations between the low-energy symmetry breaking orders, the chiral flux and charge bond orders. We find all possible 183 flux phases on Kagome lattice within 2*2 unit cell by brute-force approach and classify them by point group symmetry. Among the 183 phases, we find 3 classes in 1*1 unit cell, 8 classes in 1*2 unit cell and 18 classes in 2*2 unit cell, respectively. These results provide a full picture of the time-reversal symmetry breaking in Kagome lattices.