  Here, by making use of medium and high resolution autocorrected off-axis
electron holography, we directly probe the electrostatic potential as well as
in-plane and out-of-plane charge delocalization at edges and steps in
multilayer hexagonal boron nitride. In combination with ab-initio calculations,
the data allows to directly reveal the formation of out-of-plane covalent bonds
at folded zig-zag edges and steps comprising two monolayers and the absence of
which at monolayer steps. The technique paves the way for studying other charge
(de)localization phenomena in 2D materials, e.g., at polar edges, topological
edge states and defects.
