Controllable Floquet topological phases in the magnetic ladder system

Utilizing both the electric and magnetic fields to manipulate electron dynamics enables the external control of topological states. This study investigates the topological characteristics of a quasi-one-dimensional ladder lattice subjected to a time-periodic electric field and a constant magnetic field. The Floquet topological phases are determined in the high-frequency approximation. In the absence of a magnetic field ($\phi=0$), the energy band diagram is modulated by the electric field parameter $\alpha/\hbar\omega$, leading to a topological phase transition when $\alpha/\hbar\omega$ crosses the value of 1. When a magnetic field is present ($\phi=\pi$), the topological phase transitions in the ladder model are influenced by both the electric field parameter $\alpha/\hbar\omega$ and the perpendicular hopping $t_0$, resulting in a diverse range of adjustable topological states. These discoveries offer promising prospects for the utilization of ladder lattice systems with externally modifiable topological properties.