  Resonance plays critical roles in the formation of many physical phenomena,
and many techniques have been developed for the exploration of resonance. In a
recent letter [Phys. Rev. Lett. 117, 062502 (2016)], we proposed a new method
for probing single-particle resonances by solving the Dirac equation in complex
momentum representation for spherical nuclei. Here, we extend this method to
deformed nuclei with theoretical formalism presented. We elaborate numerical
details, and calculate the bound and resonant states in $^{37}$Mg. The results
are compared with those from the coordinate representation calculations with a
satisfactory agreement. In particular, the present method can expose clearly
the resonant states in complex momentum plane and determine precisely the
resonance parameters for not only narrow resonances but also broad resonances
that were difficult to obtain before.
