Susceptibility indicator for chiral topological orders emergent from correlated fermions

TL;DR

This paper introduces a susceptibility condition that predicts the emergence of chiral topological orders in correlated fermion systems, supported by theoretical and numerical evidence, including applications to semiconductors and frustrated magnets.

Contribution

It proposes a novel susceptibility criterion for spontaneous chiral topological order formation from interacting fermions, bridging a gap in understanding their emergence.

Findings

Identification of a susceptibility condition for chiral topological order

Discovery of a novel excitonic topological order with semionic excitations

Numerical confirmation of a chiral spin liquid state in frustrated magnets

Abstract

Chiral topological orders formed in correlated fermion systems have been widely explored. However, the mechanism on how they emerge from interacting fermions is still unclear. Here, we propose a susceptibility condition. Under this condition, we show that chiral topological orders can spontaneously take place in correlated fermion systems. The condition leads to a low-energy effective theory of bosons with strong frustration, mimicking the flat band systems. The frustration then melts the long-range orders and results in topological orders with time-reversal symmetry breaking. We apply the theory to strongly-correlated semiconductors doped to the metallic phase. A novel excitonic topological order with semionic excitations and chiral excitonic edge state is revealed. We also discuss the application to frustrated magnets. The theory predicts a chiral spin liquid state, which is numerically confirmed by our tensor network calculations. These results demonstrate an unprecedented indicator for chiral topological orders, which bridges the existing gap between interacting fermions and correlated topological matter.