  The electronic and optical response of Bernal stacked bilayer graphene with
geometry modulation and gate voltage are studied. The broken symmetry in
sublattices, one dimensional periodicity perpendicular to the domain wall and
out-of-plane axis introduces substantial changes of wavefunctions, such as
gapless topological protected states, standing waves with bonding and
anti-bonding characteristics, rich structures in density of states and optical
spectra. The wavefunctions present well-behaved standing waves in pure system
and complicated node structures in geometry-modulated system. The optical
absorption spectra show forbidden optical excitation channels, prominent
asymmetric absorption peaks, and dramatic variations in absorption structures.
These results provide that the geometry-modulated structure with tunable gate
voltage could be used for electronic and optical manipulation in future
graphene-based devices.
