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Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces

Emergent phases in the two-dimensional electron gas (2DEG) formed at the interface between two insulating oxides have attracted great attention in the past decade. We present ab-initio electronic structure calculations for the interface between a Mott insulator GdTiO(3) (GTO) and a band insulator Sr...

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Autores principales: Banerjee, Hrishit, Banerjee, Sumilan, Randeria, Mohit, Saha-Dasgupta, Tanusri
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4686895/
https://www.ncbi.nlm.nih.gov/pubmed/26689360
http://dx.doi.org/10.1038/srep18647
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author Banerjee, Hrishit
Banerjee, Sumilan
Randeria, Mohit
Saha-Dasgupta, Tanusri
author_facet Banerjee, Hrishit
Banerjee, Sumilan
Randeria, Mohit
Saha-Dasgupta, Tanusri
author_sort Banerjee, Hrishit
collection PubMed
description Emergent phases in the two-dimensional electron gas (2DEG) formed at the interface between two insulating oxides have attracted great attention in the past decade. We present ab-initio electronic structure calculations for the interface between a Mott insulator GdTiO(3) (GTO) and a band insulator SrTiO(3) (STO) and compare our results with those for the widely studied LaAlO(3)/SrTiO(3) (LAO/STO) interface between two band insulators. Our GTO/STO results are in excellent agreement with experiments, but qualitatively different from LAO/STO. We find an interface carrier density of 0.5 e(−)/Ti, independent of GTO thickness in both superlattice and thin film geometries, in contrast to LAO/STO. The superlattice geometry in LAO/STO offers qualitatively the same result as in GTO/STO. On the other hand, for a thin film geometry, the interface carrier density builds up only beyond a threshold thickness of LAO. The positive charge at the vacuum surface that compensates the 2DEG at the interface also exhibits distinct behaviors in the two systems. The compensating positive charge at the exposed surface of GTO charge disproportionates due to correlation effect making the surface insulating as opposed to that in LAO which remains metallic within band theory and presumably becomes insulating due to surface disorder or surface reconstruction.
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spelling pubmed-46868952015-12-31 Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces Banerjee, Hrishit Banerjee, Sumilan Randeria, Mohit Saha-Dasgupta, Tanusri Sci Rep Article Emergent phases in the two-dimensional electron gas (2DEG) formed at the interface between two insulating oxides have attracted great attention in the past decade. We present ab-initio electronic structure calculations for the interface between a Mott insulator GdTiO(3) (GTO) and a band insulator SrTiO(3) (STO) and compare our results with those for the widely studied LaAlO(3)/SrTiO(3) (LAO/STO) interface between two band insulators. Our GTO/STO results are in excellent agreement with experiments, but qualitatively different from LAO/STO. We find an interface carrier density of 0.5 e(−)/Ti, independent of GTO thickness in both superlattice and thin film geometries, in contrast to LAO/STO. The superlattice geometry in LAO/STO offers qualitatively the same result as in GTO/STO. On the other hand, for a thin film geometry, the interface carrier density builds up only beyond a threshold thickness of LAO. The positive charge at the vacuum surface that compensates the 2DEG at the interface also exhibits distinct behaviors in the two systems. The compensating positive charge at the exposed surface of GTO charge disproportionates due to correlation effect making the surface insulating as opposed to that in LAO which remains metallic within band theory and presumably becomes insulating due to surface disorder or surface reconstruction. Nature Publishing Group 2015-12-22 /pmc/articles/PMC4686895/ /pubmed/26689360 http://dx.doi.org/10.1038/srep18647 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Banerjee, Hrishit
Banerjee, Sumilan
Randeria, Mohit
Saha-Dasgupta, Tanusri
Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title_full Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title_fullStr Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title_full_unstemmed Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title_short Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO(3)/SrTiO(3) and LaAlO(3)/SrTiO(3) Interfaces
title_sort electronic structure of oxide interfaces: a comparative analysis of gdtio(3)/srtio(3) and laalo(3)/srtio(3) interfaces
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4686895/
https://www.ncbi.nlm.nih.gov/pubmed/26689360
http://dx.doi.org/10.1038/srep18647
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