Quantization of Au-adsorbed 5×2 domains on vicinal Si(111)
Abstract
Growth of Au-adsorbed 5×2 domains on a vicinal Si(111) surface misoriented toward the [112¯] direction is studied by scanning tunneling microscopy (STM). We find that, at a coverage of 0.3 ML, the 5×2 domains are elongated in the [01¯1] or the [1¯01] direction, not parallel to the step edge. The boundary to the Si(111)-7×7 domain shows a characteristic structure depending on whether it faces faulted or unfaulted halves. Within the 5×2 domains, several rows of bright protrusions run parallel to the boundaries. We find that the domain width dAB in the [11¯0] direction is expressed as dAB=5Nrows+5, where the Nrows is the number of rows in the domain, and the length is represented in units of the lattice constant of the 1×1 surface. Moreover, we observe that phase boundaries of the 7×7 surface are often terminated by the 5×2 domains. Then, the component of the Burgers vector along the [11¯0] direction determines the domain width dAB and the number of rows Nrows, and is found to be the remainder of (dAB+5) divided by 7. These facts mean that the values of dAB are quantized; these are discrete at intervals of 5, and are increased by 35: the number 35 is the least common multiple of the periodicities of the 7×7 and the 5×2 structure in the [11¯0] direction. We propose a growth process of the 5×2 domain based on the STM observation.
- Publication:
-
Physical Review B
- Pub Date:
- January 1998
- DOI:
- 10.1103/PhysRevB.57.2310
- Bibcode:
- 1998PhRvB..57.2310S
- Keywords:
-
- 68.35.Bs;
- 61.16.Ch;
- 68.35.Rh;
- Structure of clean surfaces;
- Phase transitions and critical phenomena