MORPHOLOGY OF MONATOMIC STEP EDGES ON VICINAL SI(001)

Article

关键词: PHASE-DIAGRAM;    SURFACES;    EQUILIBRIUM;    DIFFRACTION;    TRANSITION;    STRESS;    MODEL;   

DOI  :  10.1103/PhysRevB.48.14269

来源: SCIE

【 摘 要 】

The roughness of monatomic A- and B-type step edges on 0.5-degrees misoriented Si(001) has been analyzed on an atomic scale with scanning tunneling microscopy. On small length scales, measured along the step edge (< 200 angstrom), one-dimensional random-walk behavior is observed for both types of step edges. For the rough B-type step edge we also found evidence for waviness of the edge. The period of this wave is about 100 dimer-row spacings (almost-equal-to 750-800 angstrom). The energetic step-step interaction and entropic repulsion, which both scale as 1/L2 (L is the average terrace length), are estimated to be about 0.03-0.06 and 0.2 meV per dimer-row spacing, respectively, for a 0.5-degrees misoriented surface. These interactions are approximately three orders of magnitude smaller compared to the kink formation energies which are 0.1-0.2 eV. Despite the weak strength of energetic and entropic step-step interactions, these long-range interactions have a profound effect on the step-edge morphology, e.g., the distribution of terrace lengths and the long-range waving of the rough B-step edge.

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