Orbital angular momentum in a nonchiral topological superconductor

We investigate the bulk orbital angular momentum in a two-dimensional time-reversal broken topological superconductor with the Rashba spin-orbit interaction, the Zeeman interaction, and the $s$-wave pairing potential. Prior to the topological phase transition, we find the crossover from $s$ wave to $p$ wave. For the large spin-orbit interaction, even in the topological phase, $L_z/N$ does not reach $-1/2$, which is the intrinsic value in chiral $p$-wave superconductors. Here $L_z$ and $N$ are the bulk orbital angular momentum and the total number of electrons at zero temperature, respectively. Finally, we discuss the effects of nonmagnetic impurities.