Chemical contrast in STM imaging of transition metal aluminides

TitleChemical contrast in STM imaging of transition metal aluminides
Publication TypeJournal Article
Year of Publication2012
AuthorsDuguet T, Thiel PA
Journal TitleProgress in Surface Science
Volume87
Pages47-62
Date Published08
Type of ArticleReview
ISBN Number0079-6816
Accession NumberWOS:000308279300001
Keywords1st-principles, al-pd-mn, alloy system, alpdmn, Aluminium transition, Chemical contrast, CU, metal alloys, nial(110) surface, quasi-crystalline, relaxation, rippled, scanning tunneling microscopy, scanning-tunneling-microscopy, segregation, Valence band structure
Abstract

The present manuscript reviews recent scanning tunnelling microscopy (STM) studies of transition metal (TM) aluminide surfaces. It provides a general perspective on the contrast between Al atoms and TM atoms in STM imaging. A general trend is the much stronger bias dependence of TM atoms, or TM-rich regions of the surface. This dependence can be attenuated by the local chemical arrangements and environments. Al atoms can show a stronger bias dependence when their chemical environment, such as their immediate subsurface, is populated with TM. All this is well explained in light of combined results of STM and both theoretical and experimental electronic and crystallographic structure determinations. Since STM probes the Fermi surface, the electronic structure in the vicinity of the Fermi level (E-F) is essential for understanding contrast and bias dependence. Hence, partial density of states provides information about the TM d band position and width, s-p-d hybridization or interactions, or charge transfer between constituent elements. In addition, recent developments in STM image simulations are very interesting for elucidating chemical contrast at Al-TM alloy surfaces, and allow direct atomic identification, when the surface does not show too much disorder. Overall, we show that chemically-specific imaging is often possible at these surfaces. (C) 2012 Elsevier Ltd. All rights reserved.

URL<Go to ISI>://WOS:000308279300001
DOI10.1016/j.progsurf.2012.05.002
Alternate JournalProg. Surf. Sci.