Floquet topological phase transitions in a kicked Haldane-Chern insulator

TL;DR

This paper investigates how periodic kicking in a Haldane Chern insulator influences its topological phases, revealing a rich structure of Floquet topological transitions and phase diagram shifts driven by amplitude and frequency variations.

Contribution

It introduces a detailed analysis of Floquet topological phase transitions in a kicked Haldane model, highlighting the effects of driving parameters on phase diagram topology and symmetry breaking.

Findings

Identification of periodic 'Semenoff masses' supporting repeated phase diagrams

Discovery of two inequivalent phase diagram centers in Floquet quasienergies

Linear shift of phase diagrams with driving amplitude variations

Abstract

We consider a periodically $\delta$-kicked Haldane type Chern insulator with the kicking applied in the $\hat{z}$ direction. This is known to behave as an inversion symmetry breaking perturbation, since it introduces a time-dependent staggered sub-lattice potential. We study here the effects of such driving on the topological phase diagram of the original Haldane model of a Hall effect in the absence of a net magnetic field. The resultant Floquet band topology is again that of a Chern insulator with the driving parameters, frequency and amplitude, influencing the inversion breaking mass $M$ of the undriven Haldane model. A family of such, periodically related, `Semenoff masses' is observed to occur which support a periodic repetition of Haldane like phase diagrams along the inversion breaking axis of the phase plots. Out of these it is possible to identify two in-equivalent masses in the reduced zone scheme of the Floquet quasienergies, which form the centres of two inequivalent phase diagrams. Further, variation in the driving amplitude's magnitude alone is shown to effect the topological properties by linearly shifting the phase diagram of the driven model about the position of the undriven case. A phenomenon that allows the study of Floquet topological phase transitions in the system. Finally, we also discuss some issues regarding the modifications to Haldane's condition for preventing band overlaps at the Dirac point touchings in the Brillouin zone, in the presence of kicking.