Orbital Ordering of the Mobile and Localized Electrons at Oxygen-Deficient LaAlO3/SrTiO3 If Interfaces

被引：37

作者：

Chikina, Alla ^{[1
]}

Lechermann, Frank ^{[2
]}

Husanu, Marius-Adrian ^{[1
,3
]}

Caputo, Marco ^{[1
]}

Cancellieri, Claudia ^{[1
,4
]}

Wang, Xiaoqiang ^{[1
]}

Schmitt, Thorsten ^{[1
]}

Radovic, Milan ^{[1
]}

Strocov, Vladimir N. ^{[1
]}

机构：

[1] Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland

[2] Univ Hamburg, Inst Theoret Phys, Jungiusstr 9, DE-20355 Hamburg, Germany

[3] Natl Inst Mat Phys, Atomistilor 405A, RO-077125 Magurele, Romania

[4] Empa, Swiss Fed Labs Mat Sci & Technol, Ueberlandstr 129, CH-8600 Dubendorf, Switzerland

来源：

ACS NANO | 2018年 / 12卷 / 08期

基金：

瑞士国家科学基金会;

关键词：

LaAlO3/SrTiO3; interface; oxide interfaces; resonant photoemission; two-dimensional electron gas; oxygen vacancies; RESOLVED RESONANT PHOTOEMISSION; BEAMLINE; ADRESS; SOLVER; GAS;

D O I：

10.1021/acsnano.8b02335

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Interfacing different transition-metal oxides opens a route to functionalizing their rich interplay of electron, spin, orbital, and lattice degrees of freedom for electronic and spintronic devices. Electronic and magnetic properties of SrTiO3-based interfaces hosting a mobile two-dimensional electron system (2DES) are strongly influenced by oxygen vacancies, which form an electronic dichotomy, where strongly correlated localized electrons in the in-gap states (IGSs) coexist with noncorrelated delocalized 2DES. Here, we use resonant soft-X-ray photoelectron spectroscopy to prove the e(g) character of the IGSs, as opposed to the t(2g) character of the 2DES in the paradigmatic LaAlO3/SrTiO3 interface. We furthermore separate the d(xy) and d(xz)/d(xz) orbital contributions based on deeper consideration of the resonant photoexcitation process in terms of orbital and momentum selectivity. Supported by a self-consistent combination of density functional theory and dynamical mean field theory calculations, this experiment identifies local orbital reconstruction that goes beyond the conventional e(g)-vs-t(2g) band ordering. A hallmark of oxygen-deficient LaAlO3/SrTiO3 is a significant hybridization of the e(g) and t(2g) orbitals. Our findings provide routes for tuning the electronic and magnetic properties of oxide interfaces through "defect engineering" with oxygen vacancies.

引用

页码：7927 / 7935

页数：9

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