Correlated quantum phases and proximity effects in two dimensional magnets

• Applicants: Professor Dr. Johannes Knolle; Professorin Dr. Maria Roser Valenti
• Subject Area: Theoretical Condensed Matter Physics ; Experimental Condensed Matter Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 509751747

This project aims at studying new quantum phenomena in geometrically constrained insulating magnets by a combination of first principles methods with many-body techniques. The main objective is to use proximity effects in frustrated 2D quantum magnets to induce sought-after correlated quantum phases like topological spin liquids or topological magnon insulators. The last years have seen a flurry of new material candidates but most systems display conventional long range magnetic order at low temperatures. For example, several classes of such ’proximate spin liquids’ like α-RuCl3 now exist but an unambiguous signature of a genuine phase of this kind remains an outstanding challenge. Similarly, several layered magnets with topological magnon edge modes have been proposed but an identification of the bulk-edge correspondence in a candidate material is missing. Moreover, we will investigate whether twist engineering, which gives rise to novel correlated quantum phases in twisted semi- metals like graphene, can be used to induce and study quantum correlation phenomena also in 2D magnetic insulators. The underlying idea of this project is that the reduced dimensionality as well as proximity effects with (metallic) 2D materials can melt conventional magnetic order or induce spin-orbit effects giving rise to genuine topological magnets.

• DFG Programme: Research Grants
• International Connection: United Kingdom, USA
• Cooperation Partners: Professor Kenneth S. Burch; Professor Dr. Radu Coldea; Professor Dr. Andre Geim; Professor Erik Henriksen; Professor Dr. Igor Mazin