the annealing time.

Phase diagram {#s4}
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The stability analysis of flat (111), (211), and (110) surfaces in Sec. \[s2\_stab\] shows that at $T=0$ the (211) surface is stable for $-2\leq K<0$ whereas for $K<-2$ the (110) surface is stable. Whether these findings are generally correct we can check constructing phase diagram in the (T, K) plane by using MC simulations. Most of simulations were performed at constant K varying temperature. To check the results some simulations were performed at constant temperature. To identify different phases we calculated masses of clusters of different facet orientations (111), $\{110\}$, and $\{112\}$. A cluster of orientation (hkl) is defined in similar way as percolation cluster on the (hkl) plane. We also recorded equilibrium configurations at each investigated point of the (T, K) plane. We found that for $K<0$ the phase diagram ( see Fig. \[figure7\]) contains three phases

1.  Faceted $\{112\}$ phase consisting of 3-sided $\{112\}$ pyramids.

2.  Faceted $\{110\}$ phase consisting of 3-sided $\{110\}$ pyramids.

3.  Disordered faceted phase.

The surface of the faceted $\{110\}$ phase is built of (110), (101), and (011) facets which form 3-sided pyramids on the bcc(111) surface. Such surface has been observed experimentally in Pd on Ta(111) 