We study the quantum phases of fermions with an explicit SU(N)-symmetric,
Heisenberg-like nearest-neighbor flavor exchange interaction on the honeycomb
lattice at half-filling. Employing projective (zero temperature) quantum Monte
Carlo simulations for even values of N, we explore the evolution from a
weak-coupling semimetal into the strong-coupling, insulating regime.
Furthermore, we compare our numerical results to a saddle-point approximation
in the large-N limit. From the large-N regime down to the SU(6) case, the
insulating state is found to be a columnar valence bond crystal, with a direct
transition to the semimetal at weak, finite coupling, in agreement with the
mean-field result in the large-N limit. At SU(4) however, the insulator
exhibits a subtly different valence bond crystal structure, stabilized by
resonating valence bond plaquettes. In the SU(2) limit, our results support a
direct transition between the semimetal and an antiferromagnetic insulator.Comment: 5 pages, 6 figure