Edelstein effect in optically driven monolayer jacutingaite Pt$_2$HgSe$_3$

Abstract

The optical control of spin- and valley-selective gapless states in two-dimensional materials presents new opportunities for next-generation spintronic and valleytronic technologies. In this work, we study monolayer jacutingaite (Pt$_2$HgSe$_3$), a quantum spin Hall insulator with strong intrinsic spin-orbit coupling, under irradiation by circularly polarized light. The light-induced Floquet engineering gives rise to tunable topological phases, including transitions to spin- and valley-polarized semimetallic states. To probe these topological transitions, we employ the spin and orbital Edelstein effects -- non-equilibrium responses arising from spin-orbit interactions in systems lacking inversion symmetry -- without resorting to topological invariants such as Chern numbers. We identify universal signatures of the phase transitions encoded in the Edelstein response: a pronounced discontinuity in the spin Edelstein conductivity and a vanishing orbital Edelstein susceptibility mark the onset of the semimetallic regime. Furthermore, we investigate how the growth and suppression of the spin Edelstein responses across the topological phase transition depend on the interband scattering time. These findings establish the Edelstein effect as a sensitive and experimentally accessible probe of light-induced topological transitions in quantum materials.