  We propose a quantum electronic device based on strained graphene nanoribbon.
Mechanical strain, internal exchange field and spin-orbit couplings (SOCs) have
been exploited as principle parameters to tune physical properties of the
device. We predict a remarkable zero-field topological quantum phase transition
between the time-reversal-symmetry broken quantum spin hall (QSH) and quantum
anomalous hall (QAH) states, which was previously thought to take place only in
the presence of finite magnetic field. We illustrate as intrinsic SOC is tuned,
how two different helicity edge states located in the opposite edges of the
nanoribbon exchange their locations. Our results indicates that pseudomagnetic
field induced by the strain could be coupled to the spin degrees of freedom
through the SOC responsible for the stability of QSH state. The controllability
of this zero-field phase transition with strength and direction of the strain
is also demonstrated. Our prediction offers a tempting prospect of strain,
electric and magnetic manipulation of the QSH effect.
