Photoinduced Hall effect and transport properties of irradiated 8-Pmmn borophene monolayer

Abstract

Electronic properties of a borophene monolayer irradiated with polarized light are investigated within the average Hamiltonian approximation together with the van Vleck canonical perturbation. It is shown that varying the intensity of circularly polarized light leads to a gap opening in the single- and two-particle excitations signaling a transition from a metallic to insulating state. Simultaneously, the topology of band structure moves away from a π Berry phase, and the transversal conductivity is quantized in units of e2/h, signifying the photoinduced Hall effect. The application of linearly polarized light on borophene, on the other hand, leaves the topology of band structure intact. The interaction between electrons and photons amounts to renormalizing Fermi velocities and its signature can be traced in the density of states and longitudinal conductivity. I elaborate the discussion by examining ballistic transport of a borophene nanostructure with single and double potential barrier. In both setups, the transmission function exhibits Klein tunneling which is asymmetrically distributed with respect to the normal incidence following the anisotropy of the Fermi surface. Analysis of conductance indicates that electric signals can be enhanced and suppressed by intensity as well as helicity of light, suggesting that irradiated borophene with single and double barrier is an appealing platform for photosensitive devices.