Abstract
Precise control of lattice mismatch accommodation and interfacial cation diffusion is critical to modulate correlated functionalities in epitaxial heterostructures, particularly when the interface composition is positioned near a compositional phase transition boundary. Here we select La1-xSrxMnO3 (LSMO) as a prototype phase transition oxide and establish vertical epitaxial interfaces with NiO for exploring the strong interplay between strain accommodation, stoichiometry modification, and localized electron transport across the interface. It is found that localized stoichiometry modification overcomes the dead layer problem plaguing LSMO and leads to strongly directional conductivity, as manifested by a more than three orders of magnitude difference between out-of-plane and in-plane conductivity. Comprehensive atomic scale structural characterization and transport measurements reveal that this emerging behavior is created by a compositional change produced by preferential cation diffusion that pushes the LSMO phase transition from insulating into metallic within an ultrathin interface region. This study explores the nature of unusual electrical conductivity at vertical epitaxial interfaces and highlights the beneficial role of controllable cation diffusion that enables emerging functionalities for a broad range of potential applications such as memristors, spintronic devices, and novel nanoelectronic devices using strongly correlated materials.
| Original language | English |
|---|---|
| Pages (from-to) | 3217-3225 |
| Number of pages | 9 |
| Journal | Materials Horizons |
| Volume | 7 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2020 |
Funding
† This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). ‡ Electronic supplementary information (ESI) available. See DOI: 10.1039/d0mh01324b This work was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. Part of this research was performed at the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, which is a DOE Office of Science User Facility. This research used resources of the Center for Functional Nanomaterials and the Inner Shell Spectroscopy 8-ID beamline of the National Synchrotron Light Source II, which are U.S. DOE Office of Science User Facilities at Brookhaven National Laboratory under Contract No. DE-SC0012704. Part of TEM data collection and analysis by S. C. was supported as part of Q-MEEN-C an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under award No. DE-SC0019273. Y. Z. and operation of the electron microscopy facility at BNL were supported by DOE-BES, the Division of Materials Science and Engineering under Contract No. DE-SC0012704.
| Funders | Funder number |
|---|---|
| DOE-BES | |
| Division of Materials Science and Engineering | |
| Inner Shell | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | |
| Brookhaven National Laboratory | DE-SC0019273, DE-SC0012704 |
| Division of Materials Sciences and Engineering |