Mixed valence as a necessary criteria for quasi-two dimensional electron gas in oxide hetero-interfaces
IR@NPL: CSIR-National Physical Laboratory, New Delhi
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| Title |
Mixed valence as a necessary criteria for quasi-two dimensional electron gas in oxide hetero-interfaces
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| Creator |
Singh, Vijeta
Pulikkotil, J. J. |
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| Subject |
Applied Physics/Condensed Matter
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| Description |
The origin of quasi-two dimensional electron gas at the interface of polar-nonpolar oxide hetero-structure,such as LaAlO3/SrTiO3, is debated over electronic reconstruction and defects/disorder models. Common to these models is the partial valence transformation of substrate Ti ions from its equilibrium 4 + state to an itinerant 3 + state. Given that the Hf ions have a lower ionization potential than Ti due to the 4f orbital screening, one would expect a hetero-interface conductivity in the polar-nonpolar LaAlO3/SrHfO3 system as well. However, our first principles calculations show the converse. Unlike the Ti3+ - Ti4+ valence transition which occur at a nominal energy cost, the barrier energy associated with its isoelectronic Hf3+ - Hf4+ counterpart is very high, hence suppressing the formation of quasi-two dimensional electron gas at LaAlO3/SrHfO3 hetero-interface. These calculations, therefore, emphasize on the propensity of mixed valence at the interface as a necessary condition for an oxide hetero-structure to exihibit quasi two-dimensional electron gas.
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| Publisher |
Elsevier
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| Date |
2017-02
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://npl.csircentral.net/2787/1/Mixed%20valence%20as%20a%20necessary%20criteria.pdf
Singh, Vijeta and Pulikkotil, J. J. (2017) Mixed valence as a necessary criteria for quasi-two dimensional electron gas in oxide hetero-interfaces. Solid State Communications, 251. pp. 28-31. ISSN 0038-1098 |
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| Relation |
http://npl.csircentral.net/2787/
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