Realistic simulation of correlations & disorder in materials

A solid is a good electrical conductor if there are many electrons that can travers the material with ease. The mobility of these electrons is limited by collisions: If an electron frequently scatters with an obstacle, the electric current can decay. There are different types of obstacles that may increase the resistance to conduction: A perfect solid is a periodic array of atoms. In a real sample, however, there are always imperfections, for example atoms in the wrong place, missing atoms, or contaminations with elements not contained in the supposed chemical composition. This non-perfect atomic landscapeone speaks of disorderwill invariably hamper the flow of electrons. Electrons can also scatter with themselves. Indeed, electrons repel each other by the Coulomb force. This constrains an electrons willingness to move, as it depends onor correlates withthe location of other electrons in its vicinity. Both effects, disorder and correlations, are even able to turn an otherwise metallic material insulating. The understanding of both individual drivers of resistance has much progressed in recent years. Realistically, however, both complications are jointly present in many systems. For that case, our abilities to rationalize experimental measurements or to predict material properties or functionalities are still very limited. The goal of this project therefore is to develop theoretical methodologies and computational tools that allow simulating disorder and correlations on an equal footing. Our idea is to combine insight and techniques from different research areasstatistical physics and quantum field-theory. The ensuing synergies will make it possible to study the interplay of structural defects and electron-electron interactions in simulations of realistic materials. The to-be-developed methodologies have the potential to resolve several outstanding puzzles for specific materials that are of technological interest. More generally, they could push simulations to the point where reliable prediction of material functionalities become possible. Accounting for the real-world complications in material synthesis will significantly further the dialogue between us theoretical physicists and experimentalists or material chemists.