Physics Colloquium

Ab Initio Description of (strong) Correlation Effects in Complex van der Waals Heterostructures

by Prof. Dr. Malte Rösner

Europe/Berlin
D01-249 (UHG)

D01-249

UHG

Description

Since the seminal exfoliation of graphene, the two-dimensional allotrope of graphite, a whole library of layered materials became available. With this library we have access to semi-conducting, semi-metallic and metallic atomically thin materials, which can be easily stacked to and rotated against each other due to weak interlayer van-der-Waals interactions. The corresponding monolayer or (twisted / hetero) multilayer systems host a plethora of fascinating properties ranging from instabilities such as superconductivity, magnetism or charge order to many-body excitations such as excitons, plasmons, or magnons. All of these effects are driven by a detailed interplay between single-particle properties and strong many-body interactions in form of electron-electron (Coulomb) and electron-phonon interactions. These interactions, in turn, are sensitive to the environment of the layered material, which renders also the resulting effects dependent on the material’s surrounding.

Utilizing state-of-the-art ab initio techniques to describe Coulomb interactions in complex van der Waals heterostructures, I show how the new class of breathing-mode Kagome van-der-Waals materials Nb3X8 states a robust and versatile platform for many-body engineering prospects. Based on the environmental impact to fundamental interactions in layered materials, I further explain how spatially structured dielectric environments can externally functionalize homogeneous layered semiconductors yielding novel type-3 heterojunctions, which can potentially trap exciton complexes. 

I close the talk with an outlook to future promises of this concept including a discussion on how the applied ab initio modeling allows to link various high-level theories with material-specific experimental results and how this can be used to gain unprecedented insights into the fascinating properties of novel materials and their heterostructures.

Organized by

Thomas Dahm