Title: Physics of quantum materials: from the polymorphous theory of solids to the inverse materials design

Date: 10th of November 2023, Friday

Time: 12:00 pm (Central European Time)

Host: Silvio Osella, PhD

The seminar will be in the CeNT aula hall (00.142) on the main floor.

Abstract:

Various crystal structures can be experimentally realized, yet the number of potential combinations presents a challenge to identify compounds with the target properties for a specific application. This leads to a situation where, experimentally, the materials performance is explored in a trial-and-error probe (i.e., Edisonian approach). In this talk, we will show the alternative strategy – how knowing what the target functionality is can help us to find ways to design materials hosting such properties. This will all be done by focusing on the different types of quantum materials and demonstrating the minimal theoretical methods required to describe their properties accurately. We will revise lessons from traditional solid-state physics/chemistry textbooks that teach us that materials can generally be categorized into metals and semiconductors/insulators based on their temperature-dependent characteristics. For instance, the electronic resistivity of metals increases with rising temperature, contrasting to insulators/semiconductors that exhibit the opposite trend. Here, we will show that electronic structure theory can identify new classes of materials – gapped metals – unique compounds that share similarities with insulators, possessing an internal gap between the principal band edges, yet they retain free electrons, enabling electrical conduction akin to metals. We will show that such unique compounds often host unique properties, including mass enhancement , controllable off- stoichiometry , topological properties , or even the coexistence of transparency and high conductivity . In this way, we provide a physical understanding of the properties of such unique materials, explain knobs for controlling their properties and give a big overview of the future direction of the development of such unique materials and their potential in different technological applications.