Addressing spin order of magic-angle graphene through edge state equilibration

Electronic interactions within the flat moiré bands in magic-angle twisted bilayer graphene (MATBG) give rise to a variety of broken-symmetry ground states, including correlated Chern insulators (ChIs) that form due to unequal spin and valley occupation of the fractal Hofstadter spectrum in a magnetic field. However, there is disagreement in the literature regarding the spin-valley order of correlated states in MATBG, and the polarization of the ChIs has not been directly addressed. In this talk, I will describe a new approach to determine the spin ordering of broken-symmetry states in MATBG using a twisted graphene multilayer. By probing the backscattering between counter-propagating edge states in MATBG and a twist-decoupled graphene monolayer, we address the spin polarization of both the quantum Hall states near charge neutrality and the primary sequence of ChIs emerging from integer moiré filling factors. I will discuss the implications of our findings and future directions that build on this platform.