Emergence of Floquet edge states in the coupled Su-Schrieffer-Heeger model

TL;DR

This paper investigates how periodic driving in coupled Su-Schrieffer-Heeger chains induces non-equilibrium topological edge states, revealing new dynamical phases and pseudospin oscillation patterns that distinguish trivial and topological states.

Contribution

It demonstrates the emergence of non-equilibrium topological edge states in driven coupled SSH chains and introduces a method to identify phases via pseudospin oscillations.

Findings

Emergence of non-equilibrium edge states with topological properties

Distinct pseudospin oscillation patterns for trivial and topological phases

Observation of non-integer winding numbers in the system

Abstract

The emergence of non equilibrium topological phases in low dimensional systems offers an interesting route for material properties engineering. We analyze the dynamical modulation of two coupled one-dimensional chains, described by the Su-Schrieffer-Heeger model. We find that the interplay of driving interactions and interchain coupling leads to the emergence of non-equilibrium edge states with nontrivial topological properties. Using an effective Hamiltonian approach, we quantify the emergent topological phases via the winding number and show that oscillations in the mean pseudospin polarization arise as a consequence of the periodic modulation. The patterns of these pseudospin oscillations are different for the static trivial and topological phases offering a dynamical means to distinguish both physical configurations. The system also exhibits non integer values of the winding number, which have been recently reported experimentally in connection to spin textures.