Versatile Tunability of the Metal Insulator Transition in (TiO2)m/(VO2)m Superlattices

Gyula Eres; Shinbuhm Lee; John Nichols; Changhee Sohn; Jong Mok Ok; Alessandro R. Mazza; Chenze Liu; Gerd Duscher; Ho Nyung Lee; Daniel E. McNally; Xingye Lu; Milan Radovic; Thorsten Schmitt

doi:10.1002/adfm.202004914

Versatile Tunability of the Metal Insulator Transition in (TiO₂)_m/(VO₂)_m Superlattices

Gyula Eres, Shinbuhm Lee, John Nichols, Changhee Sohn, Jong Mok Ok, Alessandro R. Mazza, Chenze Liu, Gerd Duscher, Ho Nyung Lee, Daniel E. McNally, Xingye Lu, Milan Radovic, Thorsten Schmitt

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

7 Scopus citations

Abstract

In contrast to perovskites that share only common corners of cation-occupied octahedra, binary-oxides in addition share edges and faces increasing the versatility for tuning the properties and functionality of reduced dimensionality systems of strongly correlated oxides. This approach for tuning the electronic structure is based on the ability of X-ray spectroscopy methods to monitor the creation and transformation of occupied and unoccupied electronic states produced by interface coupling and lattice distortions. X-ray diffraction reveals a new range of structural metastability in (TiO₂)_m/(VO₂)_m/TiO₂(001) superlattices with m = 1, 3, 5, 20, 40, and electrical transport measurements show metal insulator transition (MIT) behavior typically associated with presence of high oxygen vacancy concentrations. However, X-ray absorption spectroscopy (XAS) at the Ti and V L_3,2-edge and resonant inelastic X-ray scattering (RIXS) at the Ti and V L₃-edge show no excitations characteristic of oxygen vacancy induced valance change in V and negligible intensities in Ti RIXS. The unexpected absence of oxygen vacancy related states in the X-ray spectroscopy data suggests that superlattice fabrication is capable of suppressing oxygen vacancy formation while still affording a wide tunability range of the MIT. Achieving a wide range of MIT tunability while reducing or eliminating oxygen vacancies that are detrimental to electrical properties is highly desirable for technological applications of strongly correlated oxides.

Original language	English
Article number	2004914
Journal	Advanced Functional Materials
Volume	30
Issue number	51
DOIs	https://doi.org/10.1002/adfm.202004914
State	Published - Dec 15 2020

Funding

This research was sponsored by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. This work was performed at the ADRESS beamline of the Swiss Light Source at the Paul Scherrer Institut (PSI). The work at PSI was supported by the Swiss National Science Foundation (SNSF) through the NCCR MARVEL and the Sinergia network Mott Physics Beyond the Heisenberg Model (MPBH) with SNSF grant numbers CRSII2_160765/1 and CRSII2_141962. X.L. acknowledges financial support from the European Community's Seventh Framework Programme (FP7/20072013) under Grant agreement No. 290605 (Cofund; PSI‐Fellow). T.S. was supported by SNSF, Research Grant number 200021_178867, and M.R. by SNSF Research Grant 200021_182695.

Funders	Funder number
U.S. Department of Energy
Office of Science
Basic Energy Sciences
Seventh Framework Programme	290605
Division of Materials Sciences and Engineering
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Seventh Framework Programme	200021_182695, FP7/20072013
National Center of Competence in Research Materials’ Revolution: Computational Design and Discovery of Novel Materials	CRSII2_141962, CRSII2_160765/1

Keywords

X-ray spectroscopy
binary oxide superlattices
metal insulator transitions
pulsed laser deposition
strongly correlated oxides

Access to Document

10.1002/adfm.202004914

Cite this

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title = "Versatile Tunability of the Metal Insulator Transition in (TiO2)m/(VO2)m Superlattices",

abstract = "In contrast to perovskites that share only common corners of cation-occupied octahedra, binary-oxides in addition share edges and faces increasing the versatility for tuning the properties and functionality of reduced dimensionality systems of strongly correlated oxides. This approach for tuning the electronic structure is based on the ability of X-ray spectroscopy methods to monitor the creation and transformation of occupied and unoccupied electronic states produced by interface coupling and lattice distortions. X-ray diffraction reveals a new range of structural metastability in (TiO2)m/(VO2)m/TiO2(001) superlattices with m = 1, 3, 5, 20, 40, and electrical transport measurements show metal insulator transition (MIT) behavior typically associated with presence of high oxygen vacancy concentrations. However, X-ray absorption spectroscopy (XAS) at the Ti and V L3,2-edge and resonant inelastic X-ray scattering (RIXS) at the Ti and V L3-edge show no excitations characteristic of oxygen vacancy induced valance change in V and negligible intensities in Ti RIXS. The unexpected absence of oxygen vacancy related states in the X-ray spectroscopy data suggests that superlattice fabrication is capable of suppressing oxygen vacancy formation while still affording a wide tunability range of the MIT. Achieving a wide range of MIT tunability while reducing or eliminating oxygen vacancies that are detrimental to electrical properties is highly desirable for technological applications of strongly correlated oxides.",

keywords = "X-ray spectroscopy, binary oxide superlattices, metal insulator transitions, pulsed laser deposition, strongly correlated oxides",

author = "Gyula Eres and Shinbuhm Lee and John Nichols and Changhee Sohn and Ok, {Jong Mok} and Mazza, {Alessandro R.} and Chenze Liu and Gerd Duscher and Lee, {Ho Nyung} and McNally, {Daniel E.} and Xingye Lu and Milan Radovic and Thorsten Schmitt",

note = "Publisher Copyright: {\textcopyright} 2020 Oak Ridge National Laboratory. Published by Wiley-VCH GmbH",

year = "2020",

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doi = "10.1002/adfm.202004914",

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T1 - Versatile Tunability of the Metal Insulator Transition in (TiO2)m/(VO2)m Superlattices

AU - Eres, Gyula

AU - Lee, Shinbuhm

AU - Nichols, John

AU - Sohn, Changhee

AU - Ok, Jong Mok

AU - Mazza, Alessandro R.

AU - Liu, Chenze

AU - Duscher, Gerd

AU - Lee, Ho Nyung

AU - McNally, Daniel E.

AU - Lu, Xingye

AU - Radovic, Milan

AU - Schmitt, Thorsten

PY - 2020/12/15

Y1 - 2020/12/15

N2 - In contrast to perovskites that share only common corners of cation-occupied octahedra, binary-oxides in addition share edges and faces increasing the versatility for tuning the properties and functionality of reduced dimensionality systems of strongly correlated oxides. This approach for tuning the electronic structure is based on the ability of X-ray spectroscopy methods to monitor the creation and transformation of occupied and unoccupied electronic states produced by interface coupling and lattice distortions. X-ray diffraction reveals a new range of structural metastability in (TiO2)m/(VO2)m/TiO2(001) superlattices with m = 1, 3, 5, 20, 40, and electrical transport measurements show metal insulator transition (MIT) behavior typically associated with presence of high oxygen vacancy concentrations. However, X-ray absorption spectroscopy (XAS) at the Ti and V L3,2-edge and resonant inelastic X-ray scattering (RIXS) at the Ti and V L3-edge show no excitations characteristic of oxygen vacancy induced valance change in V and negligible intensities in Ti RIXS. The unexpected absence of oxygen vacancy related states in the X-ray spectroscopy data suggests that superlattice fabrication is capable of suppressing oxygen vacancy formation while still affording a wide tunability range of the MIT. Achieving a wide range of MIT tunability while reducing or eliminating oxygen vacancies that are detrimental to electrical properties is highly desirable for technological applications of strongly correlated oxides.

AB - In contrast to perovskites that share only common corners of cation-occupied octahedra, binary-oxides in addition share edges and faces increasing the versatility for tuning the properties and functionality of reduced dimensionality systems of strongly correlated oxides. This approach for tuning the electronic structure is based on the ability of X-ray spectroscopy methods to monitor the creation and transformation of occupied and unoccupied electronic states produced by interface coupling and lattice distortions. X-ray diffraction reveals a new range of structural metastability in (TiO2)m/(VO2)m/TiO2(001) superlattices with m = 1, 3, 5, 20, 40, and electrical transport measurements show metal insulator transition (MIT) behavior typically associated with presence of high oxygen vacancy concentrations. However, X-ray absorption spectroscopy (XAS) at the Ti and V L3,2-edge and resonant inelastic X-ray scattering (RIXS) at the Ti and V L3-edge show no excitations characteristic of oxygen vacancy induced valance change in V and negligible intensities in Ti RIXS. The unexpected absence of oxygen vacancy related states in the X-ray spectroscopy data suggests that superlattice fabrication is capable of suppressing oxygen vacancy formation while still affording a wide tunability range of the MIT. Achieving a wide range of MIT tunability while reducing or eliminating oxygen vacancies that are detrimental to electrical properties is highly desirable for technological applications of strongly correlated oxides.

KW - X-ray spectroscopy

KW - binary oxide superlattices

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KW - pulsed laser deposition

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