  We study a ferromagnetic instability in a doped single-band Hubbard model by
means of dynamical mean-field theory with the continuous-time quantum Monte
Carlo simulations. Examining the effect of the strong correlations in the
system on the hypercubic and Bethe lattice, we find that the ferromagnetically
ordered state appears in the former, while it does not in the latter. We also
reveal that the ferromagnetic order is more stable in the case that the
noninteracting DOS exhibits a slower decay in the high-energy region. The
present results suggest that, in the strong-coupling regime, the high-energy
part of DOS plays an essential role for the emergence of the ferromagnetically
ordered state, in contrast to the Stoner criterion justified in the weak
interaction limit.
