Giant Faraday rotation in atomically thin semiconductors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38600090.
- Also identified by DOI 10.1038/s41467-024-47294-5 and PMC identifier 11006678.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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 WSe<sub>2</sub> and MoSe<sub>2</sub> under moderate magnetic fields. This results in the highest known Verdet constant of -1.9 × 10<sup>7</sup> deg T<sup>-1</sup> cm<sup>-1</sup> for any material in the visible regime. Additionally, interlayer excitons in hBN-encapsulated bilayer MoS<sub>2</sub> exhibit a large Verdet constant (V<sub>IL</sub> ≈ +2 × 10<sup>5</sup> deg T<sup>-1</sup> cm<sup>-2</sup>) 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 WSe<sub>2</sub> and MoSe<sub>2</sub> 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.