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Magic-angle twisted bilayer graphene (MATBG) exhibits a range of correlatedphenomena that originate from strong electron-electron interactions. Theseinteractions make the Fermi surface highly susceptible to reconstruction when $\pm 1, \pm 2, \pm 3$ electrons occupy each moir\' e unit cell and lead to theformation of correlated insulating, superconducting and ferromagnetic phases.While some phases have been shown to carry a non-zero Chern number, the localmicroscopic properties and topological character of many other phases remainelusive. Here we introduce a set of novel techniques hinging on scanningtunneling microscopy (STM) to map out topological phases in MATBG that emergein finite magnetic field. By following the evolution of the local density ofstates (LDOS) at the Fermi level with electrostatic doping and magnetic field,we visualize a local Landau fan diagram that enables us to directly assignChern numbers to all observed phases. We uncover the existence of sixtopological phases emanating from integer fillings in finite fields and whoseorigin relates to a cascade of symmetry-breaking transitions driven bycorrelations. The spatially resolved and electron-density-tuned LDOS mapsfurther reveal that these topological phases can form only in a small range oftwist angles around the magic-angle value. Both the microscopic origin andextreme sensitivity to twist angle differentiate these topological phases fromthe Landau levels observed near charge neutrality. Moreover, we observe thateven the charge-neutrality Landau spectrum taken at low fields is considerablymodified by interactions and exhibits an unexpected splitting between zeroLandau levels that can be as large as ${\sim }\,3-5$ meV. Our results show howstrong electronic interactions affect the band structure of MATBG and lead tothe formation of correlation-enabled topological phases.

Tracing out Correlated Chern Insulators in Magic Angle Twisted Bilayer Graphene