Growth and properties of strained VO x thin films with controlled stoichiometry
We have succeeded in growing epitaxial films of rocksalt VOx on MgO(001) substrates. The oxygen content as a function of oxygen flux was determined using 18O2-Rutherford backscattering spectrometry and the vanadium valence using x-ray-absorption spectroscopy. The upper and lower stoichiometry limits...
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| Hauptverfasser: | , |
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| Dokumenttyp: | Article (Journal) |
| Sprache: | Englisch |
| Veröffentlicht: |
13 February 2004
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| In: |
Physical review. B, Condensed matter and materials physics
Year: 2004, Jahrgang: 69, Heft: 7, Pages: 075404 |
| ISSN: | 1550-235X |
| DOI: | 10.1103/PhysRevB.69.075404 |
| Online-Zugang: | Verlag, Volltext: http://dx.doi.org/10.1103/PhysRevB.69.075404 Verlag, Volltext: https://link.aps.org/doi/10.1103/PhysRevB.69.075404 
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| Verfasserangaben: | A.D. Rata, A R. Chezan, M.W. Haverkort, H.H. Hsieh, H.-J. Lin, C.T. Chen, L.H. Tjeng, and T. Hibma |
| Zusammenfassung: | We have succeeded in growing epitaxial films of rocksalt VOx on MgO(001) substrates. The oxygen content as a function of oxygen flux was determined using 18O2-Rutherford backscattering spectrometry and the vanadium valence using x-ray-absorption spectroscopy. The upper and lower stoichiometry limits found are similar to those known for bulk material (0.8<x<1.3). From the reflection high-energy electron diffraction oscillation period a large number of vacancies for both vanadium and oxygen were deduced, i.e., ≈16% for stoichiometric VO. These numbers are, surprisingly, very similar to those for bulk material and consequently quite strain insensitive. X-ray-absorption spectroscopy measurements reveal that the vacancies give rise to strong non-cubic crystal field effects. The electrical conductivity of the films is much lower than the conductivity of bulk samples, which we attribute to a decrease in the direct overlap between t2g orbitals in the coherently strained layers. The temperature dependence of the conductivity is consistent with a variable range hopping mechanism. |
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| Beschreibung: | Im Titel ist "x" tiefgestellt Gesehen am 08.11.2017 |
| Beschreibung: | Online Resource |
| ISSN: | 1550-235X |
| DOI: | 10.1103/PhysRevB.69.075404 |