$\mathrm{Si}\mathrm{}\left(100\right)2\times 3-\mathrm{Na}$ surface phase: Formation and atomic arrangement

Using scanning tunneling microscopy (STM), we have studied the formation and structure of the $\mathrm{Si}\mathrm{}\left(100\right)2\times 3-\mathrm{Na}$ surface phase. It has been found that both the formation process and atomic arrangement of the $\mathrm{Si}\mathrm{}\left(100\right)2\times 3-\mathrm{Na}$ surface differ substantially from those known for $2\times 3$ reconstructions induced by other alkali and alkaline earth metals, since the Si(100)2×3-Na phase is the only one in which the top Si layer undergoes a substantial reordering. The Si-atom density in the $\mathrm{Si}\mathrm{}\left(100\right)2\times 3-\mathrm{Na}$ surface phase has been determined to be 1/3 ML. A structural model of the Si(100)2×3-Na reconstruction has been proposed, and its registry to STM images has been discussed.