are almost identical to the results in ref. , where the MF calculations were carried out for the three-band model based on {M$\sigma$, L} and assuming $U_{\textrm{M}\sigma}=U_{\textrm{L}}$. This is consistent with the fact that the present results show an almost fully occupied M$\pi$ orbital playing no role and having no dependence on $U_{\textrm{M}}$. As discussed there, the properties are governed by L orbitals. Their occupation number of 1.5 together with the rather strong dimerization are consistent with the fact that our results are analogous to the MF calculations on two-dimensional 1/4-filled Hubbard models with dimerization, e.g., as firstly performed on the model of $\kappa$-ET$_2X$[@Kino_1995JPSJ]. The existence of the AFM phase in between the AFI and PM phases is due to the imperfect nesting property of the Fermi surface, where small magnetic moments cannot produce a band splitting large enough to open up a gap on the whole Fermi surface. As long as the system is in the AFM phase, the spin moment on each site is less than 0.2 $\mu_\textrm{B}$; this is also the same as that in the three-band model. [@Seo_2008JPSJ].

### Low-temperature structure and reduced $\Delta_{\textrm{M}\sigma}^0$ {#subsubsec312}

The phase diagrams in Fig. \[fig6\](b) for the fitted results for 