MARVEL Distinguished Lecture — Kristian Sommer Thygesen


Event details

Date 23.03.2023
Hour 15:0016:15
Speaker Kristian Sommer Thygesen, Technical University of Denmark (DTU)
Location Online
Category Conferences - Seminars
Event Language English
Passcode: 4434

Prof. Kristian Sommer Thygesen

Technical University of Denmark (DTU)

Emergent Properties in Flatland: When One Plus One is More than Two
The field of 2D materials has evolved with tremendous pace over the past decade and is currently impacting many contemporary subfields of physics including spintronics, valleytronics, unconventional superconductivity, multiferroics, and quantum light sources. Van der Waals (vdW) stacking of 2D materials offers unique opportunities for creating designer structures with novel properties absent in the constituent monolayers with the emergence of superconducting phases in twisted bilayer graphenebeing a particularly striking example. Unfortunately, experimental advancements beyond the proof-of-principle level are impeded by the vast size of the configuration space defined by layer combinations and stacking orders. To improve on this situation, we use an automated density functional theory (DFT) based workflow to stack all known monolayers in all possible (non-twisted) stacking configurations. We validate the approach by comparison to experimentally observed stacking orders and compute a range of electronic, magnetic, and vibrational properties for more than 2000 homobilayers. We identify bilayers that support two or more (meta)stable stackings with different magnetic or electrical properties making them candidates for the emerging field of slidetronics. If time permits, I will discuss electrical tuning of excitons in transition metal dichalcogenide homobilayers and predictions of exciton insulators and superfluidity in Janus bilayers.

About the speaker
Prof. Thygesen develops and applies first-principles methods based on density functional theory and many-body perturbation theory to describe the electronic structure of materials with a particular focus on low-dimensional materials. He is also interested in data-driven approaches to materials design and the development of automated high-throughput workflow software. Prof. Thygesen received his PhD from the Technical University of Denmark (DTU) in 2005. Today he is heading the section for Computational Atomic-scale Materials Design (CAMD) at DTU, which is home to core developers of the GPAW electronic structure code and the Atomic Simulation Environment (ASE). He is involved in a number of international research projects including the EU Center of Excellence NOMAD.