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

TL;DR

This paper predicts a giant, frequency-selective nonlinear valley Hall effect in 2D Dirac semiconductors under terahertz fields, enabling phase-sensitive valley current control.

Contribution

It introduces a universal mechanism for resonant nonlinear valley Hall response in 2D semiconductors with broken inversion symmetry, incorporating impurity scattering effects.

Findings

Resonant cyclotron peaks in nonlinear valley Hall response.

Polarity switching of photocurrents at resonance.

Polarization-dependent valley current control.

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.