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Title: Spectroscopic properties of oxygen vacancies in LaAlO 3

Oxygen vacancies in LaAlO3 (LAO) play an important role in the formation of the 2-dimensional electron gas observed at the LaAlO3/SrTiO3 interface and affect the performance of MOSFETs using LAO as a gate dielectric. However, their spectroscopic properties are still poorly understood, which hampers their experimental identification. Here we predict the absorption spectra and ESR parameters of oxygen vacancies in LAO using periodic and embedded cluster models and Density Functional Theory (DFT). The structure, charge distribution, and spectroscopic properties of the neutral (V0O) and charged (V+O and V2+O ) oxygen vacancies in cubic and rhombohedral LaAlO3 are investigated. The highest intensity optical transitions (calculated using time dependent DFT (TDDFT)), from the oxygen vacancy states to the conduction band states have onsets at 3.5 and 4.2 eV for V0O and 3.6 eV for V+O in rhombohedral LAO and 3.3 and 4.0 eV for V 0O and 3.4 eV for V+O in cubic LAO, respectively. Also reported are the isotropic g-value (2.004026) and hyperfine coupling constants of V+O which are compared to the experimental data obtained using electron spin resonance (ESR) spectroscopy, and accurately predict both the position and the width (3 mT) of its ESR signature. These results may further facilitatemore » the experimental identification of oxygen vacancies in LAO and help to establish their role at the LAO/STO interfaces and in nanodevices using LAO.« less
Authors:
; ; ;
Publication Date:
OSTI Identifier:
1253836
Report Number(s):
PNNL-SA-116034
Journal ID: ISSN 2469-9950
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 93; Journal Issue: 13
Publisher:
American Physical Society (APS)
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English