Research assistant (praedoc) (f/m/d) (DM-PHY-968)

Freie Universität Berlin Department of Physics

The Mueller group studies nanoscale light-matter coupling phenomena in quantum materials. We use polaritons to shrink light to the nanoscale and employ ultrafast nonlinear optical techniques to bridge phenomena in the typically separate mid-infrared and visible spectral ranges. We aim to advance the understanding of 2D quantum materials, activate new coupling channels to convert light between different spectral ranges, and engineer materials through hybrid light-matter states. Our group is funded by the Emmy Noether Programme of the German Research Foundation (DFG).

The position is part of the Collaborative Research Centre CRC 1772 "mol2Dmat", which studies collective states and quantum phenomena in heterostructures of molecules and two-dimensional materials. 2D materials are atomically thin crystals that can be stacked into heterostructures with entirely new properties. CRC 1772 goes a step further by combining them with organic and inorganic molecules. The consortium brings together 20 physics and chemistry groups from Freie Universität Berlin, Humboldt-Universität zu Berlin, and Technische Universität Berlin.

Research assistant (praedoc) (f/m/d) (DM-PHY-968)

Department: Department of Physics Contract duration: limited untill 30.06.2029 Salary / pay grade: E 13 TV-L FU Working hours: 75 % Requisition ID: 968 Application deadline: 09.11.2026

Tasks

As a PhD student, you will work on the CRC project “Nonlinear imaging of structural order and symmetry breaking in mol2Dmat heterostructures” under the supervision of Dr. Niclas Mueller, starting as soon as possible. Specifically, you will:

• investigate how molecules self-assemble into ordered 2D lattices on van der Waals materials, and how collective excitonic states emerge in these heterostructures
• help build a new sum-frequency generation (SFG) microscope that combines ultrafast mid-infrared and visible lasers
• use nonlinear optical and photoluminescence microscopy to link the structural order of molecular lattices to the crystal structure of the underlying 2D material
• develop ways to tune the nonlinear optical response of these heterostructures through molecular charge transfer and electric fields