Giant resonant nonlinear THz valley Hall effect in 2D Dirac semiconductors

Abstract

We predict a giant cyclotron resonance in the nonlinear valley Hall response of inversion-asymmetric two-dimensional semiconductors subjected to crossed terahertz electric and static magnetic fields. By employing a two-band Hamiltonian that incorporates both linear and quadratic in momentum terms, thereby capturing the essential orbital texture and broken inversion symmetry, we develop a kinetic theory that accounts for antisymmetric skew scattering from impurities. Solving the Boltzmann transport equation we uncover resonant photocurrents that exhibit a sharp, polarity-switching cyclotron peak and a nontrivial polarization response dictated by the underlying D3h crystal symmetry. Our results establish a universal mechanism for frequency-selective, phase-sensitive valley current control, directly accessible in monolayer transition metal dichalcogenides. This work provides a pathway for harnessing resonant nonlinear transport in valleytronic and terahertz optoelectronic devices.