The Joint Condensed Matter Seminar (JCMS) series is organised by KTH Royal Insitute of Technology, Nordita, and Stockholm University.
On Monday, April 17th, 2023 from 11 am to 12 am we will host a seminar by Ahmed Abouelkomsan from Stockholm University.
Multiferroicity and Topology in Twisted Transition Metal Dichalcogenides
Van der Waals heterostructures have recently emerged as an exciting platform for investigating the effects of strong electronic correlations, including various forms of magnetic or electrical orders. Here, we perform an unbiased exact diagonalization study of the effects of interactions on topological flat bands of twisted transition metal dichalcogenides (TMDs) at odd integer fillings. We find that Chern insulator phases, expected from interaction-induced spin and valley polarization of the bare band structure, are quite fragile, and give way to spontaneous multiferroic order – coexisting ferroelectricity and ferromagnetism, in presence of long-range Coulomb repulsion. We provide a simple real-space picture to understand the phase diagram as a function of interaction range and strength. Our findings establish twisted TMDs as a novel and highly tunable platform for multiferroicity, with potential applications to electrical control of magnetism.
[1] arXiv:2210.14918