Magic-angle helical trilayer graphene.

The moiré patterns generated by twisting van der Waals materials has given rise to a new regime of physics in which electronic interactions and quantum geometry are at the

forefront. The unprecedented degree of tunability in these devices has led to the experimental realization of a remarkably diverse set of physical phenomena. While the

majority of studies have focused on two-layer materials, going to three or more layers vastly increases the space of possibilities, which is just beginning to be explored.

I will discuss magic-angle helical trilayer graphene (HTG), a deceptively simple structure consisting of three graphene layers with identical twist angles relative to one another.  I will show how lattice relaxation, topological flat bands, and strong interactions come together to make HTG a uniquely rich platform for realizing strongly correlated topological states and for exploring their phase transitions.