Surface state transport in irradiated topological insulator with hexagonal warping

Abstract

We investigate electronic transport in a five-region topological insulator (TI) Bi2Te3 junction with hexagonal warping under the influence of circularly polarized light (CPL). The central region is irradiated by right- and left-handed CPL, and we systematically examine how the light modifies the transport properties of the system. Within an effective theoretical framework, we study the tunability of charge conductance and magnetoresistance (MR), highlighting the role of light in controlling quantum interference and surface-state transport in TI junctions. Our results demonstrate that CPL with different helicities and intensities serves as a powerful external tuning parameter for inducing an energy gap, controlling the conductance, and generating giant MR with a tunable sign. The interplay between optical irradiation, magnetic and electrostatic potentials, geometrical parameters, and hexagonal warping leads to highly anisotropic and energy-dependent transport characteristics. These findings highlight the potential of light-driven TI devices for optoelectronic and spintronic technologies.