Using overdamped Brownian dynamics simulations we investigate the isotropic-nematic (IN) transition of self-propelled rods in three spatial dimensions.
For the well known Gay-Berne model we find that turning on activity moves to higher densities the phase boundary separating an isotropic phase from a (nonpolar) nematic phase.
This active IN phase boundary is distinct from the boundary between isotropic and polar-cluster states previously reported in two-dimensional simulation studies and, unlike the latter, is not sensitive to the system size.
We thus identify a generic feature of anisotropic active particles in three dimensions.