Coexistence of metallic edge states and anti-ferromagnetic ordering in correlated topological insulators

TL;DR

This paper explores how anti-ferromagnetic order can coexist with topological edge states in correlated topological insulators, revealing that magnetic ordering can coexist with non-trivial topological properties.

Contribution

It demonstrates, using dynamical mean-field theory, that magnetic ordering with spatial modulation can coexist with topological edge states in strongly correlated systems.

Findings

Magnetic order can coexist with topological edge states.

Topological boundary can be redefined within the system.

Edge states persist despite magnetic ordering.

Abstract

We investigate the emergence of anti-ferromagnetic ordering and its effect on the helical edge states in a quantum spin Hall insulator, in the presence of strong Coulomb interaction. Using dynamical mean-field theory, we show that the breakdown of lattice translational symmetry favours the formation of magnetic ordering with non-trivial spatial modulation. The onset of a non-uniform magnetization enables the coexistence of spin-ordered and topologically non-trivial states. An unambiguous signature of the persistence of the topological bulk property is the survival of bona fide edge states. We show that the penetration of the magnetic order is accompanied by the progressive reconstruction of gapless states in sub-peripherals layers, redefining the actual topological boundary within the system.