Light Metals on Oxygen-Terminated Diamond (100): Structure and Electronic Properties

Kane M. O'Donnell*, Tomas L. Martin, Neil L. Allan

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

14 Citations (Scopus)
398 Downloads (Pure)

Abstract

Recently a lithiated C(100)-(1 × 1):O surface has been demonstrated to possess a true negative electron affinity: that is, the conduction band minimum at the surface is lower in energy than the local vacuum level. Here we present a density functional theory study of diamond surfaces with various alkali-metal- and alkaline-earth-oxide terminations. We find a size-dependent variation of electronic surface properties that divides the adsorbates into two groups. In both cases, ether bridges are broken. Adsorption of the smaller alkali metals/alkaline earths such as lithium and magnesium leads to a significant surface dipole resulting from transfer of charge across X-O-C complexes, whereas at the other extreme, cesium- and potassium-adsorbed C(100)-(1 × 1):O surfaces exhibit conventional dipole formation between the ionic adsorbate and a negatively charged carbonyl-like surface. Sodium is intermediate. Computed surface band structures and density of states are presented, illustrating the key electronic differences between these two groups.

Original languageEnglish
Pages (from-to)1306-1315
Number of pages10
JournalChemistry of Materials
Volume27
Issue number4
DOIs
Publication statusPublished - 24 Feb 2015

Bibliographical note

Publication Date (Web): January 16, 2015

Keywords

  • diamond
  • surface chemistry
  • negative electron affinity
  • adsorption
  • density functional theory

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