Magneto-optical conductivity of monolayer transition metal dichalcogenides in the presence of proximity-induced exchange interaction and external electrical field

TL;DR

This paper provides a theoretical analysis of the magneto-optical properties of monolayer transition metal dichalcogenides, exploring how external fields and proximity effects influence their optical absorption spectra across visible and THz frequencies.

Contribution

It introduces a comprehensive theoretical framework for understanding how exchange interactions and external fields modulate MO conductivity and absorption in ML-TMDs.

Findings

Proximity-induced exchange interaction shifts absorption peaks.

External fields modulate the MO absorption spectra.

Distinct absorption features in THz and visible ranges.

Abstract

We theoretically investigate the magneto-optical (MO) properties of monolayer (ML) transition metal dichalcogenides (TMDs) in the presence of external electrical and quantizing magnetic fields and of the proximity-induced exchange interaction. The corresponding Landau Level (LL) structure is studied by solving the Schr\"odinger equation and the spin polarization in ML-TMDs under the action of the magnetic field is evaluated.The impact of trigonal warping on LLs and MO absorption is examined. Furthermore, the longitudinal MO conductivity is calculated through the dynamical dielectric function under the standard random-phase approximation (RPA) with the Kubo formula. We take ML-MoS$_2$ as an example to examine the effects of proximity-induced exchange interaction, external electrical and magnetic fields on the MO conductivity induced via intra- and interband electronic transitions among the LLs. For intraband electronic transitions within the conduction or valence bands, we can observe two absorption peaks in terahertz (THz) frequency range. While the interband electronic transitions between conduction and valence LLs show a series of absorption peaks in the visible range. We find that the proximity-induced exchange interaction, the carrier density, the strengths of the external electrical and magnetic fields can effectively modulate the positions of the absorption peaks and the shapes of the MO absorption spectra. The results obtained from this study can benefit to an in-depth understanding of the MO properties of ML-TMDs which can be potentially applied for magneto-optic, spintronic and valleytronic devices working in visible to THz frequency bandwidths.