Throughout human evolution, interactions with materials have played a defining role. The discovery and understanding of the atom in the 19th century, followed by the discovery of the electron in the 20th, propelled humanity into the Electronic Age. The successful utilization of electronics in science has opened up a plethora of new quantum effects, paving the way for promising quantum technologies — the second quantum revolution. These developments are clear indications that humanity is entering a new evolutionary stage — the Quantum Age.
The Quantum Age requires targeted synthesis of novel quantum materials based on accumulated knowledge. For quantum technologies to enter our daily lives, corresponding compounds must be designed through fine-tuning of the electronic structure. This process requires explorative approaches, including those that utilize artificial intelligence. Such approaches necessitate substantial international efforts, including funding, infrastructure, and human resources. A scientific alliance between Germany, with its advanced infrastructure and resources, and Ukraine, with its skilled human resources, could be a critical component of this international activity. The German-Ukrainian Center for Quantum Materials represents a mutually beneficial collaboration that contributes to fundamental knowledge of quantum materials and provides routes to their targeted synthesis.
AI-assisted search and optimization of quantum materials
Identifying candidate materials with potentially interesting quantum properties requires creativity, intuition, and expertise. Many elements of the electronic structure are empirically related to particular quantum properties or phenomena, including flat bands, singularities, linear dispersions, crossings of the dispersions and their degeneracies, chirality, and more. Using artificial intelligence tools to analyze numerical data is a promising strategy for solving the 'reciprocal problem' — machine learning can be used to find compounds that would host particular features in their electronic structure, or to tune those features to optimize a particular property.
Ultrafast angle-resolved photoemission experiments
Angle-resolved photoemission spectroscopy (ARPES) is an experimental technique used to study the electronic structure of solids. It allows to determine the Fermi surface - an iso-energetic surface in momentum space that separates occupied from unoccupied states - and provides information on the behavior of the most energetic electrons in the crystal. These electrons are responsible for the quantum properties of a material.
The FeSuMa spectrometer, developed by Fermiologics, is a recent innovation that streamlines and expedites the process of Fermi surface mapping. Its concept revolves around leveraging a distinct unit of information — the dataset — that can be captured while holding all other experimental parameters steady. The spectrometer employs a 2D angular distribution approach, unlike conventional analyzers that use angular-energy distribution. FeSuMa can capture a high-resolution Fermi surface map within minutes, while earlier setups can require hours. Additionally, FeSuMa has higher momentum resolution as no discrete steps are necessary, resulting in a 3D Fermi surface map that can be continuously recorded via energy changes. The integration of FeSuMa-based ARPES in thin-film and crystal growth techniques can facilitate rapid measurements of the Fermi surfaces of new materials. A FeSuMa-based ARPES setup will be installed at the joint Leibniz Lab in Kyiv during this project.