Femtosecond currents in transition metal dichalcogenides monolayers

TL;DR

This paper theoretically investigates how ultrafast intense optical pulses induce femtosecond currents in monolayer transition metal dichalcogenides, revealing symmetry-dependent charge transfer and material-specific transport behaviors.

Contribution

It provides a theoretical analysis of ultrafast optical pulse interactions with TMDC monolayers, highlighting symmetry effects and material parameter dependencies on femtosecond currents.

Findings

Pulse polarization along asymmetric directions generates both longitudinal and transverse currents.

Femtosecond currents depend on lattice constant and bandgap of TMDC materials.

Charge transfer occurs during the off-resonant ultrafast pulse interaction.

Abstract

We theoretically study the interaction of an ultrafast intense linearly polarized optical pulse with monolayers of transition metal dichalcogenides (TMDCs). Such a strong pulse redistributes electrons between the bands and generates femtosecond currents during the pulse. Due to the large bandwidth of the incident pulse, this process is completely off-resonant. While in TMDCs the time-reversal symmetry is conserved, the inversion symmetry is broken and these monolayers have the axial symmetry along armchair direction but not along the zigzag one. Therefore, the pulse polarized along the asymmetric direction of TMDC monolayer generates both longitudinal, i.e., along the direction of polarization, and transverse, i.e., in the perpendicular direction, currents. Such currents result in charge transfer through the system. We study different TMDC materials and show how the femtosecond transport in TMDC monolayers depend on their parameters, such as lattice constant and bandgap.