Cation mixing, band offsets and electric fields at LaAlO(3)/SrTiO(3)(001) heterojunctions with variable La:Al atom ratio

L Qiao; T C Droubay; T C Kaspar; P V Sushko; S A Chambers

doi:10.1016/j.susc.2011.04.035

Cation mixing, band offsets and electric fields at LaAlO(3)/SrTiO(3)(001) heterojunctions with variable La:Al atom ratio

L Qiao, T C Droubay, T C Kaspar, P V Sushko, S A Chambers

Research output: Contribution to journal › Article › peer-review

Abstract

Interfacial intermixing and electronic structure were investigated at thin (3-5 unit cells.), epitaxial La(1) _ (x)Al(1+x)O(3)/SrTiO(3)(001) heterojunctions for x = 0 and +/- 0.05. Angle-resolved X-ray photoelectron spectroscopy reveals rather extensive cation intermixing for all films, independent of composition. The valence band offset for the nominally stoichiometric (x =0) film is 0.16 +/- 0.10 eV, with the valence band maximum of SrTiO(3) being deeper in binding energy than that of LaAlO(3). Similar values are obtained for x = +/- 0.05. There is no measurable band bending in either the LaAlO(3) or the SrTiO(3) near the interface. These results are at odds with first principles theoretical predictions based on perfect stoichiometry and an abrupt interface model. However, inclusion of intermixing in the compositional description of the interface results in successful prediction of the valence band offset and absence of band bending. 2011 Published by Elsevier B.V.

Original language	English
Pages (from-to)	1381-1387
Number of pages	7
Journal	Surface Science
Volume	605
Issue number	15-16
DOIs	https://doi.org/10.1016/j.susc.2011.04.035
Publication status	Published - 2011

Keywords

LaAlO(3)/SrTiO(3) interface
Cation intermixing
INTERFACES
DENSITY
AUGER

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10.1016/j.susc.2011.04.035

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title = "Cation mixing, band offsets and electric fields at LaAlO(3)/SrTiO(3)(001) heterojunctions with variable La:Al atom ratio",

abstract = "Interfacial intermixing and electronic structure were investigated at thin (3-5 unit cells.), epitaxial La(1) _ (x)Al(1+x)O(3)/SrTiO(3)(001) heterojunctions for x = 0 and +/- 0.05. Angle-resolved X-ray photoelectron spectroscopy reveals rather extensive cation intermixing for all films, independent of composition. The valence band offset for the nominally stoichiometric (x =0) film is 0.16 +/- 0.10 eV, with the valence band maximum of SrTiO(3) being deeper in binding energy than that of LaAlO(3). Similar values are obtained for x = +/- 0.05. There is no measurable band bending in either the LaAlO(3) or the SrTiO(3) near the interface. These results are at odds with first principles theoretical predictions based on perfect stoichiometry and an abrupt interface model. However, inclusion of intermixing in the compositional description of the interface results in successful prediction of the valence band offset and absence of band bending. 2011 Published by Elsevier B.V.",

keywords = "LaAlO(3)/SrTiO(3) interface, Cation intermixing, INTERFACES, DENSITY, AUGER",

author = "L Qiao and Droubay, {T C} and Kaspar, {T C} and Sushko, {P V} and Chambers, {S A}",

note = "ISI Document Delivery No.: 804RF Times Cited: 1 Cited Reference Count: 38 Qiao, L. Droubay, T. C. Kaspar, T. C. Sushko, P. V. Chambers, S. A. ELSEVIER SCIENCE BV",

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doi = "10.1016/j.susc.2011.04.035",

language = "English",

volume = "605",

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T1 - Cation mixing, band offsets and electric fields at LaAlO(3)/SrTiO(3)(001) heterojunctions with variable La:Al atom ratio

AU - Qiao, L

AU - Droubay, T C

AU - Kaspar, T C

AU - Sushko, P V

AU - Chambers, S A

N1 - ISI Document Delivery No.: 804RF Times Cited: 1 Cited Reference Count: 38 Qiao, L. Droubay, T. C. Kaspar, T. C. Sushko, P. V. Chambers, S. A. ELSEVIER SCIENCE BV

PY - 2011

Y1 - 2011

N2 - Interfacial intermixing and electronic structure were investigated at thin (3-5 unit cells.), epitaxial La(1) _ (x)Al(1+x)O(3)/SrTiO(3)(001) heterojunctions for x = 0 and +/- 0.05. Angle-resolved X-ray photoelectron spectroscopy reveals rather extensive cation intermixing for all films, independent of composition. The valence band offset for the nominally stoichiometric (x =0) film is 0.16 +/- 0.10 eV, with the valence band maximum of SrTiO(3) being deeper in binding energy than that of LaAlO(3). Similar values are obtained for x = +/- 0.05. There is no measurable band bending in either the LaAlO(3) or the SrTiO(3) near the interface. These results are at odds with first principles theoretical predictions based on perfect stoichiometry and an abrupt interface model. However, inclusion of intermixing in the compositional description of the interface results in successful prediction of the valence band offset and absence of band bending. 2011 Published by Elsevier B.V.

AB - Interfacial intermixing and electronic structure were investigated at thin (3-5 unit cells.), epitaxial La(1) _ (x)Al(1+x)O(3)/SrTiO(3)(001) heterojunctions for x = 0 and +/- 0.05. Angle-resolved X-ray photoelectron spectroscopy reveals rather extensive cation intermixing for all films, independent of composition. The valence band offset for the nominally stoichiometric (x =0) film is 0.16 +/- 0.10 eV, with the valence band maximum of SrTiO(3) being deeper in binding energy than that of LaAlO(3). Similar values are obtained for x = +/- 0.05. There is no measurable band bending in either the LaAlO(3) or the SrTiO(3) near the interface. These results are at odds with first principles theoretical predictions based on perfect stoichiometry and an abrupt interface model. However, inclusion of intermixing in the compositional description of the interface results in successful prediction of the valence band offset and absence of band bending. 2011 Published by Elsevier B.V.

KW - LaAlO(3)/SrTiO(3) interface

KW - Cation intermixing

KW - INTERFACES

KW - DENSITY

KW - AUGER

U2 - 10.1016/j.susc.2011.04.035

DO - 10.1016/j.susc.2011.04.035

M3 - Article

SN - 0039-6028

VL - 605

SP - 1381

EP - 1387

JO - Surface Science

JF - Surface Science

IS - 15-16

ER -

Cation mixing, band offsets and electric fields at LaAlO(3)/SrTiO(3)(001) heterojunctions with variable La:Al atom ratio

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Keywords

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