Topological Electronics and Materials: Research
Project Module
Proximity control of van der Waals heterostructures
Van der Waals materials and their heterostructures are a versatile solid-state platform to engineer and explore topological states. To this end, we interface different van der Waals materials with different symmetries manipulating the relevant electronic properties at the atomic level.
Currently, we explore spin-orbit and magnetic proximity interactions in graphene-based vdW heterostructures of 2D materials on a fundamental level. We study the spintronic and magnetotransport properties of the heterostructures and their control via charge tuning, layer number, quality of the material interfaces, as well as the crystallographic alignment of the monolayers.
The work is supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) within the Priority Programme SPP 2244 2DMP “Physics of van der Waal heterostructures” (project ID 443274823).
Collaborators: Prof. Alexander Holleitner (TUM), Dr. Marko Burghard (MPI-FKF, Stuttgart).
Publications
Project Module
Topological light matter coupling
We study light-matter-interactions in quantum materials which are dominated by topological effects. For materials exhibiting dispersive bands with a narrow gap and strong spin-orbit coupling, the photon polarization couples to the Berry curvature of the Bloch states, whereas for materials exhibiting flat bands, the photon polarization couples to the quantum metric of the Bloch states.
These quantum geometric properties become important in the context of many-body correlations, since, for example, they are thought to be key in understanding exotic phases, such as flat-band superconductivity.
To access these topological properties, we utilize a resonant mid-infrared excitation (4 µm – 18 µm) at the relevant interband energies, and we detect the optical selection rules by an electronic measurement.
Publications
Project Module
Nanofabricated topological materials
One of the pillars of today’s nanotechnology is the ability to precisely control the spatial symmetries and spatial extents of quantum states confined into nanostructures, either by top-down or bottom-up approaches. Our group utilizes the He-ion microscope operated at the ZNN to structure topological materials at scales below 10 nm.
Our recent ERC starting grant project Top-Down Superlattice Engineering of 2D Solid-State Quantum Matter investigates emergent quantum states in nanofabricated superlattice structures. The project focuses on two-dimensional materials with strong spin-orbit coupling and non-trivial band topologies to establish their potential as functional spin-electronic and optoelectronic devices in semiconductor and quantum technologies.
2DTopS is funded through the European Union’s Horizon Europe Research and Innovation Programme under Grant Agreement No 101076915.
Proximity control of van der Waals heterostructures
Van der Waals materials and their heterostructures are a versatile solid-state platform to engineer and explore topological states. To this end, we interface different van der Waals materials with different symmetries manipulating the relevant electronic properties at the atomic level.
Topological light matter coupling
We study light-matter-interactions in quantum materials which are dominated by topological effects. For materials exhibiting dispersive bands with a narrow gap and strong spin-orbit coupling, the photon polarization couples to the Berry curvature of the Bloch states, whereas for materials exhibiting flat bands, the photon polarization couples to the quantum metric of the Bloch states.
Nanofabricated topological materials
One of the pillars of today’s nanotechnology is the ability to precisely control the spatial symmetries and spatial extents of quantum states confined into nanostructures, either by top-down or bottom-up approaches. Our group utilizes the He-ion microscope operated at the ZNN to structure topological materials at scales below 10 nm.