Resonant Raman and Hyper-Raman scattering in two-dimensional transition metal dichalcogenides in an external magnetic field: Magneto polaron effects

• Grant number: 22/08825-8
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: July 09, 2023
• End date: June 08, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Gilmar Eugenio Marques
• Grantee: Gilmar Eugenio Marques
• Visiting researcher: Carlos Luis Trallero Giner
• Visiting researcher institution: Universidad de La Habana (UH), Cuba
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

In the present project, we propose to explore two main problems. The first one (A) is related to the study of the Raman and Hyper-Raman scattering in two-dimensional (2D) transition metal dichalcogenides (TMD) in a strong applied external magnetic field. The task is devoted to a study the first order Resonant Raman (RR) and non-linear Resonant Hyper- Raman (RHR) scattering in MX2 monolayer (ML) (M = Mo, W and X = S, Se,Te). We will derive a general formalism for RR and RHR scattering by optical phonons valid at any laser energy and external magnetic field. We report the electron-photon and electron-phonon of interactions valid for 2D TMD crystals and address to the influence of magnetic field and magneto-polaron effects on RR and RHR efficiencies. We will study the two main allowed intravalley electron-phonon Hamiltonians: deformation potential (DP) and Fröhlich (F). The second topic (B) is linked to polaron and magneto-polaron effects in TMD. The dependence of the polaron energy with the magnetic field is known to be particular interesting for magneto-optical properties andmagneto-Raman scattering. Understanding of magneto-polaron phenomena in ML TMD play a crucial role for a correct description of magneto RR and HRR intensities. Hence, an important task is to know the magneto-polaron properties for the MX 2 monolayer and their effects on Raman processes. Typically, resonant magneto-polaron coupling occurs due to the electron-phonon interaction, when two Landau levels, N and M, are separated by the energy of one optical phonon and we observe that each Landau level splits into two branches. The inclusion of magneto- polaron properties on the Raman tensor and the hyper-Raman intensity is a challenge from the theoretical and experimental points of view. (AU)