Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice

TL;DR

This paper demonstrates the existence of Floquet-Weyl and Floquet-topological-insulator phases in a stacked 2D ring-network lattice, revealing Weyl points, Fermi-arc surface states, and chiral surface states through quasienergy spectrum analysis.

Contribution

It introduces a novel stacked 2D ring-network lattice model exhibiting Floquet-Weyl and Floquet-topological-insulator phases, with detailed phase diagram and potential optical realization.

Findings

Weyl points and Fermi-arc surface states identified in quasienergy spectrum.

Chiral surface states coexist in the Weyl phase.

Two gapless surface states in the Floquet-topological-insulator phase.

Abstract

We show the presence of Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice. The Weyl points in the three-dimensional Brillouin zone and Fermi-arc surface states are clearly demonstrated in the quasienergy spectrum of the system in the Weyl phase. In addition, chiral surface states coexist in this phase. The Floquet-topological-insulator phase is characterized by the winding number of two in the reflection matrices of the semi-infinite system and resulting two gapless surface states in the quasienergy g ap of the bulk. The phase diagram of the system is derived in the two-parameter space of hopping S-matrices among the rings. We also discuss a possible optical realization of the system together with the introduction of synthetic gauge fields.