Quenching in Chern insulators with satellite Dirac points: The fate of edge states

TL;DR

This study investigates the non-equilibrium dynamics of a generalized Haldane model with satellite Dirac points, revealing that edge currents decay in finite systems post-quench despite unchanged bulk topological invariants.

Contribution

It demonstrates the persistence of Chern numbers after quenches across topological phases and uncovers the decay behavior of edge currents in finite systems with complex Dirac point structures.

Findings

Chern number remains unchanged after quenches between topological phases.

Edge currents decay to zero in finite systems when quenched to non-topological phases.

Inner edge channels decay faster than outer channels during certain quenches.

Abstract

We perform a sudden quench on the Haldane model with long range interactions, more specifically generalising to the next to next nearest neighbour hopping, referred to as the $N3$ model in our work. Such a model possesses both isotropic and multiple anisotropic (satellite) Dirac points which lead to a rich topological phase diagram consisting of phases with higher Chern number ($C$). Quenches between the topological and the non-topological phases of such an infinite system probe the effect of the presence of the anisotropic Dirac points on the non-equilibrium response of the topological system. Interestingly, the Chern number remains the same before and after the quench for both the quenching protocols, even when the quench of the system is carried out between two different topological phases. {However, for a finite system, we establish that the initial edge current asymptotically decays to zero when the system is quenched to the non-topological phase although the Chern number for the corresponding periodically wrapped system remains unaltered; what is remarkable is that when the Hamiltonian is quenched from $|C|=2$ phase to the non-topological phase the edge current associated with the inner channel decays at a faster rate than the outer channel resembling a situation in which the system passes through the phase with $|C|=1$ before ending up in the phase $C=0$.