Ab-initio calculation of C and CO adsorption on the Co (110) surface

Shin-Liang Chin*, Adrian Ionescu, Robert M. Reeve, Jun Cheng, Crispin H. W. Barnes

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The adsorption energies, structural, electrical and magnetic properties of adsorption of C and CO on the fcc Co (110) surface have been investigated using density functional theory. The preferential adsorption site for the fcc Co (110) has been calculated. For the case of C adsorption, the preferential adsorption site is the long-bridge for both the 0.5 and 1.0 monolayers (ML) coverages. Whilst for the CO case, the preferential adsorption sites are at the atop and short-bridge site for 0.5 and 1.0 ML coverages respectively. Structurally, the first two layers of the bare Co (110) surface expand whereas the second and third layers contract. Upon adsorption of either C or CO, however, the degree of expansion and compression reduces. Magnetically, the adsorbates were found to couple ferrimagnetically to the surface and suppress the magnetic moment of the Co layers beneath them. The C adsorbate has a much stronger suppression effect as compared to the CO adsorbate. At 0.5 ML coverage, the C adatom suppresses up to 47% of the magnetic moment in the surface layer compared to a clean Co (110), whereas the CO adsorbate only suppresses up to 16%. For the 1.0 ML coverage case, both the C and CO adsorbates suppress almost equivalently well at 68% and 63% respectively. We also report on a correlation between the amount of charge transfer and the degree of suppression of the surface magnetic moment. Finally, we observe that the electronic charge is shared in the [001] direction for the C adsorbate and in the [1 (1) over bar0] direction for the CO adsorbate. This anisotropy of surface bonding, in conjunction with the ligand field theory, explains the mechanism behind the spin reorientation transition that occurs uniquely on the CO/Co(110) system. (C) 2012 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)282-291
Number of pages10
JournalSurface Science
Volume608
Early online date2 Nov 2012
DOIs
Publication statusPublished - Feb 2013

Keywords

  • spin-reorientation transition
  • density functional calculations
  • chemisorption
  • adsorbates
  • magnetic surfaces
  • magnetic thin films
  • cobalt
  • tight-binding
  • density-functional theory
  • generalized gradient approximation
  • Fischer-Tropsch catalysts
  • magnetic-anisotropy
  • multilayer relaxation
  • CO/CU(110) films
  • orbital moments
  • 1st principles

Cite this

Chin, S-L., Ionescu, A., Reeve, R. M., Cheng, J., & Barnes, C. H. W. (2013). Ab-initio calculation of C and CO adsorption on the Co (110) surface. Surface Science , 608, 282-291. https://doi.org/10.1016/j.susc.2012.10.020

Ab-initio calculation of C and CO adsorption on the Co (110) surface. / Chin, Shin-Liang; Ionescu, Adrian; Reeve, Robert M.; Cheng, Jun; Barnes, Crispin H. W.

In: Surface Science , Vol. 608, 02.2013, p. 282-291.

Research output: Contribution to journalArticle

Chin, S-L, Ionescu, A, Reeve, RM, Cheng, J & Barnes, CHW 2013, 'Ab-initio calculation of C and CO adsorption on the Co (110) surface', Surface Science , vol. 608, pp. 282-291. https://doi.org/10.1016/j.susc.2012.10.020
Chin, Shin-Liang ; Ionescu, Adrian ; Reeve, Robert M. ; Cheng, Jun ; Barnes, Crispin H. W. / Ab-initio calculation of C and CO adsorption on the Co (110) surface. In: Surface Science . 2013 ; Vol. 608. pp. 282-291.
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T1 - Ab-initio calculation of C and CO adsorption on the Co (110) surface

AU - Chin, Shin-Liang

AU - Ionescu, Adrian

AU - Reeve, Robert M.

AU - Cheng, Jun

AU - Barnes, Crispin H. W.

PY - 2013/2

Y1 - 2013/2

N2 - The adsorption energies, structural, electrical and magnetic properties of adsorption of C and CO on the fcc Co (110) surface have been investigated using density functional theory. The preferential adsorption site for the fcc Co (110) has been calculated. For the case of C adsorption, the preferential adsorption site is the long-bridge for both the 0.5 and 1.0 monolayers (ML) coverages. Whilst for the CO case, the preferential adsorption sites are at the atop and short-bridge site for 0.5 and 1.0 ML coverages respectively. Structurally, the first two layers of the bare Co (110) surface expand whereas the second and third layers contract. Upon adsorption of either C or CO, however, the degree of expansion and compression reduces. Magnetically, the adsorbates were found to couple ferrimagnetically to the surface and suppress the magnetic moment of the Co layers beneath them. The C adsorbate has a much stronger suppression effect as compared to the CO adsorbate. At 0.5 ML coverage, the C adatom suppresses up to 47% of the magnetic moment in the surface layer compared to a clean Co (110), whereas the CO adsorbate only suppresses up to 16%. For the 1.0 ML coverage case, both the C and CO adsorbates suppress almost equivalently well at 68% and 63% respectively. We also report on a correlation between the amount of charge transfer and the degree of suppression of the surface magnetic moment. Finally, we observe that the electronic charge is shared in the [001] direction for the C adsorbate and in the [1 (1) over bar0] direction for the CO adsorbate. This anisotropy of surface bonding, in conjunction with the ligand field theory, explains the mechanism behind the spin reorientation transition that occurs uniquely on the CO/Co(110) system. (C) 2012 Elsevier B.V. All rights reserved.

AB - The adsorption energies, structural, electrical and magnetic properties of adsorption of C and CO on the fcc Co (110) surface have been investigated using density functional theory. The preferential adsorption site for the fcc Co (110) has been calculated. For the case of C adsorption, the preferential adsorption site is the long-bridge for both the 0.5 and 1.0 monolayers (ML) coverages. Whilst for the CO case, the preferential adsorption sites are at the atop and short-bridge site for 0.5 and 1.0 ML coverages respectively. Structurally, the first two layers of the bare Co (110) surface expand whereas the second and third layers contract. Upon adsorption of either C or CO, however, the degree of expansion and compression reduces. Magnetically, the adsorbates were found to couple ferrimagnetically to the surface and suppress the magnetic moment of the Co layers beneath them. The C adsorbate has a much stronger suppression effect as compared to the CO adsorbate. At 0.5 ML coverage, the C adatom suppresses up to 47% of the magnetic moment in the surface layer compared to a clean Co (110), whereas the CO adsorbate only suppresses up to 16%. For the 1.0 ML coverage case, both the C and CO adsorbates suppress almost equivalently well at 68% and 63% respectively. We also report on a correlation between the amount of charge transfer and the degree of suppression of the surface magnetic moment. Finally, we observe that the electronic charge is shared in the [001] direction for the C adsorbate and in the [1 (1) over bar0] direction for the CO adsorbate. This anisotropy of surface bonding, in conjunction with the ligand field theory, explains the mechanism behind the spin reorientation transition that occurs uniquely on the CO/Co(110) system. (C) 2012 Elsevier B.V. All rights reserved.

KW - spin-reorientation transition

KW - density functional calculations

KW - chemisorption

KW - adsorbates

KW - magnetic surfaces

KW - magnetic thin films

KW - cobalt

KW - tight-binding

KW - density-functional theory

KW - generalized gradient approximation

KW - Fischer-Tropsch catalysts

KW - magnetic-anisotropy

KW - multilayer relaxation

KW - CO/CU(110) films

KW - orbital moments

KW - 1st principles

U2 - 10.1016/j.susc.2012.10.020

DO - 10.1016/j.susc.2012.10.020

M3 - Article

VL - 608

SP - 282

EP - 291

JO - Surface Science

JF - Surface Science

SN - 0039-6028

ER -