Optically Controlled Topological Phases in the Deformed $\alpha -T_3$ Lattice

Abstract

Haldane's tight-binding model, which describes a Chern insulator in a two-dimensional hexagonal lattice, exhibits quantum Hall conductivity without an external magnetic field. Here, we explore an $\alpha -T_3$ lattice subjected to circularly polarized off-resonance light. This lattice, composed of two sublattices (A and B) and a central site (C) per unit cell, undergoes deformation by varying the hopping parameter ${\gamma }_1$ while keeping ${\gamma }_2$= ${\gamma }_3$= $\gamma$. Analytical expressions for quasi-energies in the first Brillouin zone reveal significant effects of symmetry breaking. Circularly polarized light lifts the degeneracy of Dirac points, shifting the cones from M. This deformation evolves with ${\gamma }_1$, breaking symmetry at ${\gamma }_1=2\gamma$, as observed in Berry curvature diagrams. In the standard case (${\gamma }_1=\gamma$), particle-hole and inversion symmetries are preserved for $\alpha =0$ and . The system transitions from a semi-metal to a Chern insulator, with band-specific Chern numbers: $C_2=1$, $C_1=0$, and $C_0=-1$ for shifting to $C_2=2$, $C_1=0$, and $C_0=-2$ when For ${\gamma }_1>2\gamma$, the system enters a trivial insulating phase. These transitions, confirmed via Wannier charge centers, are accompanied by a diminishing Hall conductivity. Our findings highlight tunable topological phases in $\alpha -T_3$ lattices, driven by light and structural deformation, with promising implications for quantum materials.

References in corpus (19)

• Topological Photonics
• Z2Pack: Numerical Implementation of Hybrid Wannier Centers for Identifying Topological Materials
• Irradiated graphene as a tunable Floquet topological insulator
• Light-induced emergent phenomena in 2D materials and topological materials
• Topological flat band models with arbitrary Chern numbers
• Floquet topological phase transition in $\alpha$-${\mathcal{T}}_3$ lattice
• Distant-Neighbor Hopping in Graphene and Haldane Models
• Floquet Weyl semimetal phases in light-irradiated higher-order topological Dirac semimetals
• Four Dimensional Graphene
• Probing Topological signatures in an optically driven $\alpha$-$T_3$ Lattice
• Strain-induced pseudo-magnetic field in $\alpha -{\mathcal{T}}_3$ lattice
• Topological features of Haldane model on a dice lattice: role of flat band on transport properties
• Floquet engineering of topological phase transitions in quantum spin Hall $\alpha$-$T_3$ system
• Higher order topological matter and fractional chiral states
• Holstein polaron in a pseudospin-$1$ quantum spin Hall system: first and second order topological phase transitions
• Anomalous transport in pseudospin-1 fermions
• BerryEasy: A GPU enabled python package for diagnosis of nth-order and spin-resolved topology in the presence of fields and effects
• Band engineered bilayer Haldane model: Evidence of multiple topological phase transitions
• High Chern numbers and topological flat bands in high-field polarized Kitaev magnets on the star lattice

Cited by in corpus (2)

• Extended Haldane Model in The Dice Lattice: Multiple Flat-Band-Induced topological Transitions Revealed
• Valley- and Orbital-Controlled 2D Chern Insulators Without Spin-orbit Interaction