Evidence for correlated states in a topological van der Waals monolayer.*

Introducing electron correlations to topological materials can lead to the emergence of new quantum states of matter.  We found that natural topological van der Waals (vdW) crystals MM′X4 (M = Nb, Ta and M′ = Ir, Rh) could be an exciting new platform to study the interplay of correlation and topology. In this talk, we report experimental evidence as well as tentative theoretical understanding of correlated states in a monolayer MM′X4.