Abstract
Our scanning tunneling microscope studies on clean surfaces of fivefold icosahedral Al 70.2 Pd 20.7 Mn 9.1 reveal that, after annealing at 900K, two types of flat depressions are visible on terraces: voids (small, shallow, flat-bottomed depressions bordered by 2.5 Å steps) and pits (deeper, and often larger, depressions). They are different not only in their dimensions but in their behavior: voids preferentially nucleate on some of the terraces and, after annealing at 925 K, their coalescence and growth leads a new type of termination to be exposed. Pits, however, do not destroy the terraces on which they exist, under the experimental conditions. At the bottom of 4.1Å-deep pits, 2.5 Å-deep voids nucleate, so that the total depth of the pit is 6.6 Å. We propose that 2.5 Å void-rich terraces are metastable terminations, and that these metastable terminations are also exposed at the bottom of the 4.1 Å-deep pits.
Original language | English |
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Pages (from-to) | 819-824 |
Number of pages | 6 |
Journal | Philosophical Magazine |
Volume | 86 |
Issue number | 6-8 |
DOIs | |
State | Published - Feb 21 2006 |
Externally published | Yes |
Funding
This work was supported by the Director, Office of Science of Basic Energy Science, Materials Science Division of the U.S. Department of Energy under Contract No. W-405-Eng-82.