  We give a self-contained derivation of the low-energy effective interactions
of the SU($N$) Hubbard model, a multiflavor generalization of the one-band
Hubbard model, by using a generalized Schrieffer-Wolff transformation (SWT).
The effective interaction of doublons and holons, which has been largely
ignored in previous SWT studies (e.g., the $t$-$J$ model), leads to distinct
peaks in the local density of states. As shown by Lee et al. [Phys. Rev. Lett.
119, 236402 (2017)], this underlying effective doublon-holon interaction
explains the numerical observation of the subpeaks at the inner edges of the
Hubbard bands in the metallic phase close to the Mott transition.
