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Oxygen Stoichiometry Effect on Polar Properties of LaAlO 3 /SrTiO 3
Author(s) -
Sharma Pankaj,
Huang Zhen,
Li Mengsha,
Li Changjian,
Hu Songbai,
Lee Hyungwoo,
Lee JungWoo,
Eom ChangBeom,
Pennycook Stephen J.,
Seidel Jan,
Gruverman Alexei
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201707159
Subject(s) - materials science , heterojunction , ferroelectricity , stoichiometry , piezoelectricity , characterization (materials science) , oxide , nanotechnology , chemical physics , oxygen , polar , condensed matter physics , thin film , optoelectronics , engineering physics , dielectric , chemistry , composite material , physics , organic chemistry , astronomy , engineering , metallurgy
Discovery of a ferroelectric‐like behavior of the LaAlO 3 /SrTiO 3 (LAO/STO) interfaces provides an attractive platform for the development of nanoelectronic devices with functionality that can be tuned by electrical or mechanical means. However, further progress in this direction critically depends on deeper understanding of the physicochemical mechanism of this phenomenon. In this report, this problem by testing the electronic properties of the LAO/STO heterostructures with oxygen stoichiometry used as a variable is addressed. Local probe measurements in conjunction with interface electrical characterization allow to establish the field‐driven reversible migration of oxygen vacancies as the origin of the ferroelectric‐like behavior in LAO/STO. In addition, it is shown that oxygen deficiency gives rise to the formation of micrometer‐long atomically sharp boundaries with robust piezoelectricity stemming from a significant strain gradient across the boundary region. These boundaries are not ferroelectric but they can modulate the local electronic characteristics at the interface. The obtained results open a possibility to design and engineer electromechanical functionality in a wide variety of nominally nonpolar and non‐piezoelectric complex oxide heterostructures and thin films.