Quantum Phase Transition in Phosphate Glasses Containing Multiple Transition Metal Oxides
| Autor: | Mark Henderson, Rudra P. Bhatta, Biprodas Dutta, Ian L. Pegg, Andreza Eufrasio |
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| Rok vydání: | 2019 |
| Předmět: |
Quantum phase transition
Materials science Condensed matter physics chemistry.chemical_element Vanadium Tungsten Condensed Matter Physics Polaron Electronic Optical and Magnetic Materials Ion chemistry Transition metal Electrical resistivity and conductivity Materials Chemistry Charge carrier Electrical and Electronic Engineering |
| Zdroj: | Journal of Electronic Materials. 48:3105-3114 |
| ISSN: | 1543-186X 0361-5235 |
| Popis: | The evidence for a Mott–Hubbard type metal–insulator transition (MIT) is presented in the xP2O5− yV2O5− (100− x − y)WO3 glass system (PVW) at a critical concentration of tungsten (W) ions. Electrons contributed by the reduced vanadium (V) and tungsten (W) ions are self-trapped to form small polarons, and the hopping motion of such charge carriers is the universally accepted transport mechanism. Whereas both the V and W ions are present in multiple oxidation states in these glasses, charges at the V4+ (reduced) sites contribute only to electrical conduction. We demonstrate that, in PVW glasses, electrons at the reduced tungsten sites are too strongly localized to contribute to electrical conduction, but the oxidized state still contributes an available orbital for electrons to tunnel through. This secondary contribution of the tungsten ions greatly facilitates small polaron hopping (SPH) conductivity. With decreasing vanadium concentration [nV= V/(V + W), where V and W are the molar concentrations of V and W ions in this equation], as the inter-atomic distance between V ions increases, the resistivity remains invariant in the composition range 0.5 |
| Databáze: | OpenAIRE |
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