Engineered substrates and synthetic superlattices

Superlattices are artificial, periodic potentials which are used to confined particles and quasiparticles such as atoms, electrons, or excitons. Particles trapped in a superlattice can form simulated crystals, and, through particle-particle interactions, become strongly correlated. By controlling parameters such as the superlattice filling factor, spin statistics, particle type, and by tuning particle-particle interactions, one can realize a wide variety of quantum phenomena. Examples include superfluidity, correlated insulating states, superconductivity, topological bands, and magnetism. Superlattice structures can also be used to guide and manipulate single particles, to create unique lattice-based electronic, excitonic, and spintronic devices for quantum networks.

Our goal is to create superlattices to trap excitons in 2D semiconductors via substrate engineering. Our approach capitalizes on the precision and reproducibility of conventional lithography techniques while exploiting van der Waals fabrication to create heterostructures with ultra-low disorder.

Relevant publications

Excitons and emergent quantum phenomena in stacked 2D semiconductors

Collaborators

Andreas Stier (WSI)

Matteo Barbone (TUM - ZNN)

2D magnetic semiconductors

The chromium chalcogen halides (CrXH) are an emerging family of 2D semiconductors with a direct bandgap, highly anisotropic structural and electronic properties, and robust magnetic order with ordering temperatures up to room temperature. We seek to understand and engineer interactions between the magnetic order in CrXH compounds and the excitons they host. The unique magnetic and optical properties of CrXH materials present unique opportunities to develop spintronic devices with magnetic and optical controllability.

Relevant publications

Excitons in a 2D magnetic semiconductor

Giant Magnetoresistance in spin-filter van der Waals heterostructures

Collaborators

Andreas Stier (TUM - WSI)

Zdenek Sofer (VSCHT Prague)

Clement Faugeras (LNCMI, CNRS Grenoble)

Jacek Kasprzak (Institut Néel, CNRS Grenoble)

Christian Back/Lin Chen (TUM - Physics, MCQST)