Charge waves and dynamical signatures of topological phases in Su-Schrieffer-Heeger chains

TL;DR

This paper explores charge wave dynamics in SSH topological chains, revealing that transient charge oscillations can serve as real-time signatures of topological phases, especially at edges.

Contribution

It demonstrates that charge oscillations occur in topological SSH chains and can be used to distinguish topological phases through dynamical signatures at edges.

Findings

Charge oscillations can occur in gapped topological systems with chiral symmetry.

Edge charge dynamics differ significantly between topological phases.

Quench dynamics reveal clear signatures distinguishing trivial and nontrivial phases.

Abstract

We investigate the emergence of charge waves and their temporal dynamics in one-dimensional Su-Schrieffer-Heeger (SSH) topological chains. Contrary to the conventional view that charge oscillations are suppressed in gapped topological systems with preserved chiral symmetry, we show that such oscillations can indeed occur. The general condition for an arbitrary oscillation period is analysed, and we find that the charge waves propagating along the chain do not depend on its topology, except at the edges, where both topological phases exhibit essential differences. In chains with inequivalent atoms within the SSH unit cell, we observe regular long-period sublattice oscillations that appear simultaneously with even-odd charge oscillations. Furthermore, we study the nonequilibrium dynamics in SSH chains. After a quench, the time evolution of the local density of states and charge occupancies exhibits clear dynamical fingerprints that distinguish topologically trivial and nontrivial phases. Our results establish that transient charge dynamics can distinguish topologically trivial and nontrivial phases in real time by detecting the presence of topologically-protected edge states.