Giant Faraday rotation in atomically thin semiconductors

Carey, Benjamin and Wessling, Nils Kolja and Steeger, Paul and Schmidt, Robert and Michaelis de Vasconcellos, Steffen and Bratschitsch, Rudolf and Arora, Ashish (2024) Giant Faraday rotation in atomically thin semiconductors. Nature Communications, 15 (1). 3082. ISSN 2041-1723 (

[thumbnail of Carey-etal-NC-2024-Giant-Faraday-rotation-in-atomically-thin-semiconductors]
Text. Filename: Carey-etal-NC-2024-Giant-Faraday-rotation-in-atomically-thin-semiconductors.pdf
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (1MB)| Preview


Faraday rotation is a fundamental effect in the magneto-optical response of solids, liquids and gases. Materials with a large Verdet constant find applications in optical modulators, sensors and non-reciprocal devices, such as optical isolators. Here, we demonstrate that the plane of polarization of light exhibits a giant Faraday rotation of several degrees around the A exciton transition in hBN-encapsulated monolayers of WSe2 and MoSe2 under moderate magnetic fields. This results in the highest known Verdet constant of -1.9 × 107 deg T−1 cm−1 for any material in the visible regime. Additionally, interlayer excitons in hBN-encapsulated bilayer MoS2 exhibit a large Verdet constant (VIL ≈ +2 × 105 deg T−1 cm−2) of opposite sign compared to A excitons in monolayers. The giant Faraday rotation is due to the giant oscillator strength and high g-factor of the excitons in atomically thin semiconducting transition metal dichalcogenides. We deduce the complete in-plane complex dielectric tensor of hBN-encapsulated WSe2 and MoSe2 monolayers, which is vital for the prediction of Kerr, Faraday and magneto-circular dichroism spectra of 2D heterostructures. Our results pose a crucial advance in the potential usage of two-dimensional materials in ultrathin optical polarization devices.