  Domain walls, topological defects that define the frontier between regions of
different stacking in multilayer graphene, have proved to host exciting
physics. The ability of tuning these topological defects in-situ in an
electronic transport experiment brings a wealth of possibilities in terms of
fundamental understanding of domain walls as well as for electronic
applications. Here, we demonstrate through a MEMS (micro-electromechanical
system) actuator and magnetoresistance measurements the effect of domain walls
in multilayer graphene quantum Hall effect. Reversible and controlled uniaxial
strain triggers these topological defects, manifested as new quantum Hall
effect plateaus as well as a discrete and reversible modulation of the current
across the device. Our findings are supported by theoretical calculations and
constitute the first indication of the in-situ tuning of topological defects in
multilayer graphene probed through electronic transport, opening the way to the
use of reversible topological defects in electronic applications.
