at $\rho = 0.838$. Optimized values of $M$ are plotted in Fig. \[fig:sdwM\]. Since finite $t'$ deteriorates the nesting property of the Fermi surface, the energy gain per site in the SDW state should decrease with introduction of negative $t'$. The calculated values for $t' = -0.10$ is shown in Fig. \[fig:gain-r2\] by closed diamonds. The energy gain per site in the SC state given by closed circles increases when $t'=-0.10$. The phase boundary between the two is estimated at about 0.873 as the intersection of the extrapolation of the line linking the two closed diamonds and the curve for the SC energy gain per site with $t' = - 0.10$. So the boundary is pushed up by $\Delta \rho = 0.035$ but not enough as to move the boundary up to $\rho = 0.95$, the observed boundary in La$_{2-x}$Sr$_x$CuO$_4$. The obtained phase diagram in the $t'$-$\rho$ plane is shown in Fig. \[fig:phasedi\].

Comparison with Experiments and Other Results
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Energy Gain per Site in the SC State
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By means of the cell-perturbation method, Feiner et al. were able to reduced the $d$-$p$ model into an effective one-band Hubbard model \[\]. In their result the transfer energy $t$ slightly 