Authors

E. Z. Ciftlikli; L. V. Goncharova; B. J. Hinch; M. A. Ortigoza; S. Hong;T. S. Rahman

Comments

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Abbreviated Journal Title

Phys. Rev. B

Keywords

SCANNING-TUNNELING-MICROSCOPY; CU(100)-C(2X2)N SURFACE; PHONON-DISPERSION; SELF-ORGANIZATION; RECONSTRUCTION; CU(100); LEED; IMAGES; ENERGY; CU(100)C(2X2)-N; Physics, Condensed Matter

Abstract

Helium-atom scattering and density-functional perturbation theory (DFPT) calculations invoking the linear-response approximation and the pseudopotential approach have been used to study the vibrational dynamics of c(2x2)-like phases produced by nitrogen-ion implantation and subsequent annealing of Cu(001) surfaces. We find that, while the c(2x2) phonon dispersion relations are different from those of clean Cu(001), neither the acoustic nor the optical surface phonon mode energies measured along both [100] and [110] directions are dependent on N coverage once the c(2x2) pattern is formed. We show that the dispersion of the surface phonon modes is well reproduced with an analysis of the DFPT calculations of a nonstress relieved c(2x2) structure. A marked softening of a zone center optical mode is very apparent both experimentally and in the calculations. We show this softening arises largely because of interplanar Cu surface relaxations induced by N adsorption.

Journal Title

Physical Review B

Volume

81

Issue/Number

11

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

11

WOS Identifier

WOS:000276248800178

ISSN

1098-0121

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