MARVEL seminar: "Designing excited states for energy and quantum-information applications" (Felipe H. da Jornada)

Designing excited states for energy and quantum-information applications

Felipe H. da Jornada

Department of Materials Science and Engineering, Stanford University, CA, USA

The performance of most electronic and optical devices, from transistors to solar cells, is typically dictated by how they react to external stimuli – i.e., by their excited-state properties. While first-principles methods based on density-functional theory and many-body perturbation theory can access such properties, such methods are often restricted to perturbative settings and limited to simulating small systems and short time scales. We will discuss how recent advances, which give us two orders of magnitude speed-ups in such calculations, allow us to predict the excited-state properties of complex materials and use such excited states to achieve novel optoelectronic and photocatalytic functionalities. We will discuss the complex interplay between excitons and large-scale atomistic relaxation in moiré patterns that emerge in twisted materials, as well as how non-thermal phonon distributions can increase the thermal coupling of van-der-Waals-stacked layered materials. Finally, we will show how we can actively predict excited states for chemical reactions in a realistic heterogeneous photocatalyst involving TiO₂, opening the exciting prospect of systematically unraveling novel energy-efficient chemical reaction pathways for sustainable chemistry.

About the speaker

Felipe H. da Jornada is an Assistant Professor in the Department of Materials Science and Engineering at Stanford University. Before joining Stanford, Felipe received his Ph.D. in physics from UC Berkeley working with Prof. Steven G. Louie. He received the best thesis award from the Kavli Energy NanoScience Institute at UC Berkeley (2017) and the National Science Foundation CAREER award (2023). Felipe has ample experience understanding the electronic and optical properties of atomically thin materials – such as graphene and mono- and few-layer transition metal dichalcogenides (TMDs) – using first-principles computational approaches. More broadly, he is interested in employing a combination of new theoretical formalisms and massively parallel computer calculations to understand new excited-state phenomena in materials with applications in energy research, physics at reduced dimensions, and quantum information.