Document Type

Article

Publication Date

11-19-2010

Abstract

We have studied two surfaces of a new Al–Pd–Zn approximant using mass spectrometry, X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). Zn is bonded weakly in this approximant, perhaps as weakly as in elemental Zn. This is based upon three observations: (1) the low vapor pressure of Zn above the approximant (detectable in the gas phase at 600 K), (2) preferential sputtering of Zn (contrary to the usual preferential sputtering of Al in Al-rich quasicrystals), and (3) preferential surface segregation of Zn. We further show that preferential segregation – and perhaps incipient evaporation – causes the surface to roughen, preventing it from forming a terrace-step morphology. Finally, our data show that at low O2 pressures, Al oxidizes. In air, Zn oxidizes as well. All results and conclusions are similar for the two-fold and pseudo-10-fold surfaces.

Comments

This article was originally published in Philosophical Magazine 91, nos. 19–21 (1–21 July 2011): 2879–2888, by Taylor & Francis. DOI: 10.1080/14786435.2010.528458.

Rights

This article is (co-)authored by an employee of the United States Government and is not subject to copyright in the United States (17 U.S.C. §105).

Language

en

File Format

application/pdf

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