Abstract
Coadsorption of Na with CO2 and H2O on a thin Cr2O3(111) single crystal epitaxially grown on a single-crystal Cr(110) substrate has been performed to study the effects of the coadsorbates on the electronic properties of the Na species. High-resolution electron-energy-loss spectroscopy spectra as a function of Na overlayer coverage reveal a continuous attenuation of the Fuchs-Kliewer surface-phonon loss modes with near total attenuation by ∼2 monolayers (ML). Coadsorption with either H2O or CO2 returns the substrate Fuchs-Kliewer modes to a relative intensity approximately equal to that observed on the clean Cr2O3(111) surface. Angle-resolved photoemission spectroscopy (ARPES) measurements from the Cr2O3(111) surface demonstrate almost total attenuation of the Cr2O3(111) valence-band emission by a Na coverage of ∼2 ML with no return of Cr2O3(111) valence-band emission features upon coadsorption. These observations provide strong evidence that the development of a metallic Na overlayer results in a damping of the coupling interaction between the electron and the Fuchs-Kliewer phonons and that upon reaction with the coadsorbed species, a uniform dielectric overlayer is formed which permits the return of the Fuchs-Kliewer losses. The metallic-to-nonmetallic transition of the overlayer is also supported by the ARPES data which reveal suppression of emission from the Fermi level, the disappearance of the LVV Auger transition, and a shifting to higher binding energy of the Na 2p emission upon compound formation during coadsorption.
| Original language | English |
|---|---|
| Pages (from-to) | 12892-12895 |
| Number of pages | 4 |
| Journal | Physical Review B |
| Volume | 46 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - 1992 |
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ASJC Scopus subject areas
- Condensed Matter Physics
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Metallic-to-nonmetallic transition of Na coadsorbed with CO2 and H2O on the Cr2O3(111)/Cr(110) surface. / Ventrice, C. A.; Ehrlich, D.; Garfunkel, Eric; Dillmann, B.; Heskett, D.; Freund, H. J.
In: Physical Review B, Vol. 46, No. 19, 1992, p. 12892-12895.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Metallic-to-nonmetallic transition of Na coadsorbed with CO2 and H2O on the Cr2O3(111)/Cr(110) surface
AU - Ventrice, C. A.
AU - Ehrlich, D.
AU - Garfunkel, Eric
AU - Dillmann, B.
AU - Heskett, D.
AU - Freund, H. J.
PY - 1992
Y1 - 1992
N2 - Coadsorption of Na with CO2 and H2O on a thin Cr2O3(111) single crystal epitaxially grown on a single-crystal Cr(110) substrate has been performed to study the effects of the coadsorbates on the electronic properties of the Na species. High-resolution electron-energy-loss spectroscopy spectra as a function of Na overlayer coverage reveal a continuous attenuation of the Fuchs-Kliewer surface-phonon loss modes with near total attenuation by ∼2 monolayers (ML). Coadsorption with either H2O or CO2 returns the substrate Fuchs-Kliewer modes to a relative intensity approximately equal to that observed on the clean Cr2O3(111) surface. Angle-resolved photoemission spectroscopy (ARPES) measurements from the Cr2O3(111) surface demonstrate almost total attenuation of the Cr2O3(111) valence-band emission by a Na coverage of ∼2 ML with no return of Cr2O3(111) valence-band emission features upon coadsorption. These observations provide strong evidence that the development of a metallic Na overlayer results in a damping of the coupling interaction between the electron and the Fuchs-Kliewer phonons and that upon reaction with the coadsorbed species, a uniform dielectric overlayer is formed which permits the return of the Fuchs-Kliewer losses. The metallic-to-nonmetallic transition of the overlayer is also supported by the ARPES data which reveal suppression of emission from the Fermi level, the disappearance of the LVV Auger transition, and a shifting to higher binding energy of the Na 2p emission upon compound formation during coadsorption.
AB - Coadsorption of Na with CO2 and H2O on a thin Cr2O3(111) single crystal epitaxially grown on a single-crystal Cr(110) substrate has been performed to study the effects of the coadsorbates on the electronic properties of the Na species. High-resolution electron-energy-loss spectroscopy spectra as a function of Na overlayer coverage reveal a continuous attenuation of the Fuchs-Kliewer surface-phonon loss modes with near total attenuation by ∼2 monolayers (ML). Coadsorption with either H2O or CO2 returns the substrate Fuchs-Kliewer modes to a relative intensity approximately equal to that observed on the clean Cr2O3(111) surface. Angle-resolved photoemission spectroscopy (ARPES) measurements from the Cr2O3(111) surface demonstrate almost total attenuation of the Cr2O3(111) valence-band emission by a Na coverage of ∼2 ML with no return of Cr2O3(111) valence-band emission features upon coadsorption. These observations provide strong evidence that the development of a metallic Na overlayer results in a damping of the coupling interaction between the electron and the Fuchs-Kliewer phonons and that upon reaction with the coadsorbed species, a uniform dielectric overlayer is formed which permits the return of the Fuchs-Kliewer losses. The metallic-to-nonmetallic transition of the overlayer is also supported by the ARPES data which reveal suppression of emission from the Fermi level, the disappearance of the LVV Auger transition, and a shifting to higher binding energy of the Na 2p emission upon compound formation during coadsorption.
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U2 - 10.1103/PhysRevB.46.12892
DO - 10.1103/PhysRevB.46.12892
M3 - Article
AN - SCOPUS:0001066937
VL - 46
SP - 12892
EP - 12895
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 19
ER -