Project Details
Projekt
Advanced van der Waals heterostructures with magnetic and ferroelectric components
Subject Area
Experimental Condensed Matter Physics
Term
since 2024
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 549364913
In our project, we aim to achieve new levels of control over excitons in van der Waals (vdW) heterostructures (HS). We will study, both, intralayer excitons in different transition metal dichalcogenides (TMDCs), and interlayer excitons (IX), which are hosted in heterobilayers (HBL) of different TMDCs. IX in these systems are characterized by long lifetimes and diffusion lengths and may also acquire a valley polarization. The properties of IX can be tailored to some extent by controlling HBL composition and interlayer alignment, but we aim to achieve more control over diffusion and valley polarization. To this end, we will introduce additional functional layers. On one hand, these will be various layered magnetic materials, such as Cr2Ge2Te6 (ferromagnetic semiconductor), Fe3GeTe2 (metallic ferromagnet), or CrSBr (layered A-type antiferromagnet). These can, for example, introduce Zeeman splitting via magnetic proximity effects. On the other hand, we will utilize 3R-stacked MoS2, which is an interfacial ferroelectric material that can, both, host IX directly, and provide a ferroelectric potential landscape for excitons in more complex vdW HS. In our study, we will utilize advanced spectroscopy systems that evolved in the Regensburg and Rostock groups in recent years, such as imaging micro-photoluminescence for tracking exciton diffusion and two-color Kerr rotation for layer-selective excitation and probing of dynamics. Many of the available setups complement each other, so that, e.g., near-resonant pump-probe experiments on diselenides can be carried out in Regensburg, while similar experiments on disulfides can be performed in Rostock. The combined experience and infrastructure for sample preparation developed by both groups will be shared to further improve interlayer coupling and spatial homogeneity by applying advanced fabrication techniques such as hot pickup and deterministic transfer in inert environment.
DFG Programme
Research Grants
