If set to true, and using complex states, complex spherical harmonics will be used, i.e.
with $e^{\pm i m \phi}$.
If false, real spherical harmonics with $\sin(m \phi)$ or $\cos(m \phi)$ are used.
This variable will make it more likely to get states that are eigenvectors of the $L_z$
operator, with a definite angular momentum.