Condensed Matter Physics Seminar: Magnus Hårdensson Berntsen

Abstract: Quantum materials – such as high-temperature superconductors, two-dimensional crystals, and topological systems – host exotic phases of matter that challenge our understanding of condensed matter physics and hold promise for future technologies. A central key to unraveling their properties lies in understanding their electronic structure: how electrons move, interact, and organize under different conditions.
Angle-resolved photoemission spectroscopy (ARPES) has emerged as a powerful tool in this pursuit, providing direct access to the momentum- and energy-resolved electronic states of these complex systems. 
In this talk, I will briefly introduce the basic concepts of ARPES, highlighting both static and time-resolved approaches, and discuss how they enable us to visualize quasiparticles, band structures, and many-body interactions. I will then give an overview of our newly developed instrument for time-resolved ARPES (Baltazar lab at KTH) as well as examples from our recent work on quantum materials – including high-/T/_c superconductors, layered two-dimensional systems, and topological matter – illustrating how ARPES sheds light on the mechanisms driving their unusual behavior. Finally, I will highlight our recent progress on Cooper-pair spectroscopy, an emerging technique that may open a fresh window into the mechanisms underlying high-temperature superconductivity.