Mapping quantum Hall edge states in graphene by scanning tunneling microscopy

Edge states are the fingerprint of topological materials, specifically of the quantum Hall effect. The authors map quantum Hall edge states along an electrostatically defined potential step in graphene using scanning tunneling microscopy. Tight-binding simulations reproduce the measurements and allow for identifying a parameter range that minimizes the influence of the tip. This enables investigating the edge states while avoiding tip-induced quantum dots within the sample. The image shows a measured edge state featuring the expected antinodal patterns as it meanders along the interface.