High yield assembly of designer twisted 2D vdW hetero-structures

Principal investigator

Dmitri K. Efetov, LMU München [webpage]

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Abstract

Two-dimensional (2D) crystals can be extracted from a variety of bulk van der Waals (vdW) materials, and assembled on top of each other into vertical hetero-structures. By choosing a precise sequence of assembly one can engineer complex designer materials with strong electronic interactions and enhanced quantum effects, and tune these with electrical and magnetic fields. As the vdW layers can be assembled with an arbitrary crystallographic angle between them, this enables an entirely new concept – Twistronics, where the mismatch between two similar lattices generates a “moire” pattern. For two graphene layers, twisted with a well defined “magic” angle of 1.1°, ultra-flat bands are formed, and give rise to superconductivity.

In this project we will develop novel automatized assembly techniques to prepare twisted “moire” materials composed out of a variety of parent vdW materials (graphene and TMD bilayers and multilayers) with a high yield and homogeneity. In such devices we will be able to study the phasediagrams of these materials in the clean limit and to obtain a reproducible view on their correlated, superconducting and topological properties.