SI(100)2X3-NA SURFACE PHASE - FORMATION AND ATOMIC ARRANGEMENT

Using scanning tunneling microscopy (STM), we have studied the formati on and structure of the Si(100)2 x 3-Na surface phase. It has been fou nd that both the formation process and atomic arrangement of the Sit 1 00)2 x 3-Na surface differ substantially from those known for 2 x 3 re constructions induced by other alkali and alkaline earth metals, since the Si(100)2x3-Na phase is the only one in which the top Si layer und ergoes a substantial reordering. The Si-atom density in the Si(100)2x3 -Na surface phase has been determined to be 1/3 ML. A structural model of the Si(100)2x3-Na reconstruction has been proposed, and its regist ry to STM images has been discussed.