Quantum anomalous Hall (QAH) insulators are topological phases of matter that host one-dimensional chiral edge states that result in unidirectional electrical current flow, quantized Hall conductance, and dissipationless carrier transport. We have used scanning tunneling microscopy and spectroscopy to directly visualize and manipulate chiral edge states in a moiré QAH insulator made from twisted monolayer-bilayer graphene. We are able to control the Chern number in our device by tuning the carrier concentration, thus stabilizing adjacent domains having opposite Chern number and enabling the visualization of chiral edge states residing at domain interfaces independent of any structural boundaries within our sample. Formation of tip-induced quantum dots provides additional local control over the carrier density and Chern number, enabling the creation of chiral edge states with desired chirality at predetermined locations. Our approach of combining visualization of QAH chiral edge states with full electrical control creates new possibilities for exploring the exotic topological properties of QAH insulators.
21 pages, 9 figures