Anomalous Ultrafast All-Optical Hall Effect in Gapped Graphene

TL;DR

This paper introduces a theoretical framework for inducing an ultrafast all-optical anomalous Hall effect in gapped 2D materials like graphene, enabling femtosecond-scale control of Hall currents for potential ultrafast information processing.

Contribution

It proposes a novel ultrafast all-optical Hall effect mechanism in 2D semiconductors using a sequence of tailored femtosecond laser pulses, driven by topological resonance effects.

Findings

Demonstrates the feasibility of inducing femtosecond Hall currents

Identifies topological resonance as key to the effect

Suggests applications in ultrafast optical data storage

Abstract

We propose an ultrafast all-optical anomalous Hall effect in two-dimensional (2D) semiconductors of hexagonal symmetry such as gapped graphene (GG), transition metal dichalcogenides (TMDCs), and hexagonal boron nitride (h-BN). To induce such an effect, the material is subjected to a sequence of two strong-field single-optical-cycle pulses: a chiral pump pulse followed within a few femtoseconds by a probe pulse linearly polarized in the armchair direction of the 2D lattice. Due to the effect of topological resonance, the first (pump) pulse induces a large chirality (valley polarization) in the system, while the second pulse generates a femtosecond pulse of the anomalous Hall current. The proposed effect is the fundamentally the fastest all-optical anomalous Hall effect possible in nature. It can be applied to ultrafast all-optical storage and processing of information, both classical and quantum.