Mechanism and energetics for step merging on a metallic surface captured with scanning tunneling microscopy

• Published in: Surface science Vol. 496; no. 1; pp. L29 - L34
• Main Authors: Pearl, T.P., Sibener, S.J.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 2002; Amsterdam Elsevier Science; New York, NY
• Subjects: Chemisorption; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Nickel; Oxygen; Physics; Scanning tunneling microscopy; Solid surfaces and solid-solid interfaces; Stepped single crystal surfaces; Surface structure and topography; Surface structure, morphology, roughness, and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Vicinal single crystal surfaces; Chemisorption; Scanning tunneling microscopy; Oxygen; Stepped single crystal surfaces; Vicinal single crystal surfaces; Nickel; Surface structure, morphology, roughness, and topography; Vicinal surface; Surface defect; Transition elements; Crystal faces; Rough surfaces; Surface topography; Experimental study; STM; Surface energy; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(01)01637-5

Scanning tunneling microscopy has been used to observe oxygen induced microfaceting of Ni(9 7 7) in the temperature range of 390–565 K. Step doubling occurs on this surface provided the step-edges are locally decorated with oxygen. In this letter, time-lapse images of this process have been used to resolve two key steps of the coalescence mechanism. Merging of steps is initiated by the bulging of one step in the downstairs direction towards its neighbor. This rate limiting step is followed by the second mechanistic process, namely zippering of adjacent steps. Merging step contact angles have been analyzed to extract information on the energetics of step–step interactions. These results give a real-space view of the atomic-level surface structural changes which accompany the initial stages of metallic oxidation of interfaces containing extended surface defects.