Utilizing quantum effects in complex oxides, such as magnetism, multiferroicity and superconductivity, requires atomic-level control of the material’s structure and composition. In contrast, the continuous conductivity changes that enable artificial oxide-based synapses and multiconfigurational devices are driven by redox reactions and domain reconfigurations, which entail long-range ionic migration and changes in stoichiometry or structure. Although both concepts hold great technological potential, combined applications seem difficult due to the mutually exclusive requirements. Here we demonstrate a route to overcome this limitation by controlling the conductivity in the functional oxide hexagonal Er(Mn,Ti)O3 by using conductive atomic force microscopy to generate electric-field induced anti-Frenkel defects, that is, charge-neutral interstitial–vacancy pairs. These defects are generated with nanoscale spatial precision to locally enhance the electronic hopping conductivity by orders of magnitude without disturbing the ferroelectric order. We explain the non-volatile effects using density functional theory and discuss its universality, suggesting an alternative dimension to functional oxides and the development of multifunctional devices for next-generation nanotechnology.
This is a preview of subscription content, access via your institution
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
Prices may be subject to local taxes which are calculated during checkout
Computer codes used for simulations and data evaluation are available from the sources cited; data in formats other than those presented within this paper are available from the corresponding authors upon request.
Seok Jeong, D., Kim, I., Ziegler, M. & Kohlstedt, H. Towards artificial neurons and synapses: a materials point of view. RSC Adv. 3, 3169–3183 (2013).
Ielmini, D. & Wong, H. S. P. In-memory computing with resistive switching devices. Nat. Electron. 1, 333–343 (2018).
Del Valle, J., Ramírez, J. G., Rozenberg, M. J. & Schuller, I. K. Challenges in materials and devices for resistive-switching-based neuromorphic computing. J. Appl. Phys. 124, 211101 (2018).
Chanthbouala, A. et al. A ferroelectric memristor. Nat. Mater. 11, 860–864 (2012).
Hwang, H. Y. et al. Emergent phenomena at oxide interfaces. Nat. Mater. 11, 103–113 (2012).
Ramesh, R. & Schlom, D. G. Creating emergent phenomena in oxide superlattices. Nat. Rev. Mater. 4, 257–268 (2019).
Lee, J. S., Lee, S. & Noh, T. W. Resistive switching phenomena: a review of statistical physics approaches. Appl. Phys. Rev. 2, 31303 (2015).
Cen, C. et al. Nanoscale control of an interfacial metal–insulator transition at room temperature. Nat. Mater. 7, 298–302 (2008).
Du, N. et al. Field-driven hopping transport of oxygen vacancies in memristive oxide switches with interface-mediated resistive switching. Phys. Rev. Appl. 10, 54025 (2018).
Wang, X. et al. Anisotropic resistance switching in hexagonal manganites. Phys. Rev. B 99, 054106 (2019).
Nagarajan, L. et al. A chemically driven insulator–metal transition in non-stoichiometric and amorphous gallium oxide. Nat. Mater. 7, 391–398 (2008).
Cava, R. J. et al. Oxygen stoichiometry, superconductivity and normal-state properties of YBa2Cu3O7-δ. Nature 329, 423–425 (1987).
Zhao, J. et al. Lattice and magnetic structures of PrFeAsO, PrFeAsO0.85F0.15, and PrFeAsO0.85. Phys. Rev. B 78, 132504 (2008).
Kalinin, S. V., Jesse, S., Tselev, A., Baddorf, A. P. & Balke, N. The role of electrochemical phenomena in scanning probe microscopy of ferroelectric thin films. ACS Nano 5, 5683–5691 (2011).
Maier, J. Physical Chemistry of Ionic Materials: Ions and Electrons in Solids (Wiley, 2004).
Kumar, A., Ciucci, F., Morozovska, A. N., Kalinin, S. V. & Jesse, S. Measuring oxygen reduction/evolution reactions on the nanoscale. Nat. Chem. 3, 707–713 (2011).
Holstad, T. S. et al. Electronic bulk and domain wall properties in B-site doped hexagonal ErMnO3. Phys. Rev. B 97, 85143 (2018).
Chae, S. C. et al. Direct observation of the proliferation of ferroelectric loop domains and vortex–antivortex pairs. Phys. Rev. Lett. 108, 167603 (2012).
Van Aken, B. B., Palstra, T. T. M., Filippetti, A. & Spaldin, N. A. The origin of ferroelectricity in magnetoelectric YMnO3. Nat. Mater. 3, 164–170 (2004).
Han, M.-G. et al. Ferroelectric switching dynamics of topological vortex domains in a hexagonal manganite. Adv. Mater. 25, 2415–2421 (2013).
Skjærvø, S. H. et al. Interstitial oxygen as a source of p-type conductivity in hexagonal manganites. Nat. Commun. 7, 13745 (2016).
Skjærvø, S. H., Småbråten, D. R., Spaldin, N. A., Tybell, T. & Selbach, S. M. Oxygen vacancies in the bulk and at neutral domain walls in hexagonal YMnO3. Phys. Rev. B 98, 184102 (2018).
Remsen, S. & Dabrowski, B. Synthesis and oxygen storage capacities of hexagonal Dy1–xY xMnO3+δ. Chem. Mater. 23, 3818–3827 (2011).
Bergum, K. et al. Synthesis, structure and magnetic properties of nanocrystalline YMnO3. Dalton Trans. 40, 7583–7589 (2011).
Bi, F. et al. ‘Water-cycle’ mechanism for writing and erasing nanostructures at the LaAlO3/SrTiO3 interface. Appl. Phys. Lett. 97, 173110 (2010).
Schaab, J. et al. Electrical half-wave rectification at ferroelectric domain walls. Nat. Nanotechnol. 13, 1028–1034 (2018).
Katsufuji, T. et al. Dielectric and magnetic anomalies and spin frustration in hexagonal RMnO3 (R = Y, Yb, and Lu). Phys. Rev. B 64, 104419 (2001).
Zhang, Q. H. et al. Direct observation of interlocked domain walls in hexagonal RMnO3 (R = Tm, Lu). Phys. Rev. B 85, 20102 (2012).
Holtz, M. E. et al. Topological defects in hexagonal manganites: inner structure and emergent electrostatics. Nano Lett. 17, 5883–5890 (2017).
Fennie, C. J. & Rabe, K. M. Ferroelectric transition in YMnO3 from first principles. Phys. Rev. B 72, 100103 (2005).
Artyukhin, S., Delaney, K. T., Spaldin, N. A. & Mostovoy, M. Landau theory of topological defects in multiferroic hexagonal manganites. Nat. Mater. 13, 42–49 (2013).
Cano, A. Hidden order in hexagonal RMnO3 multiferroics (R = Dy, Lu, In, Y, and Sc). Phys. Rev. B 89, 214107 (2014).
Mundy, J. A. et al. Functional electronic inversion layers at ferroelectric domain walls. Nat. Mater. 16, 622–627 (2017).
Tan, H., Verbeeck, J., Abakumov, A. & Van Tendeloo, G. Oxidation state and chemical shift investigation in transition metal oxides by EELS. Ultramicroscopy 116, 24–33 (2012).
Nishida, S. et al. Effect of local coordination of Mn on Mn-L2,3 edge electron energy loss spectrum. J. Appl. Phys. 114, 54906 (2013).
Loomer, D. B., Al, T. A., Weaver, L. & Cogswell, S. Manganese valence imaging in Mn minerals at the nanoscale using STEM-EELS. Am. Mineral. 92, 72–79 (2007).
Garvie, L. A. J. & Craven, A. J. High-resolution parallel electron energy-loss spectroscopy of Mn L2,3-edges in inorganic manganese compounds. Phys. Chem. Miner. 21, 191–206 (1994).
Rehr, J. J., Kas, J. J., Vila, F. D., Prange, M. P. & Jorissen, K. Parameter-free calculations of X-ray spectra with FEFF9. Phys. Chem. Chem. Phys. 12, 5503–5513 (2010).
Overton, A. J., Best, J. L., Saratovsky, I. & Hayward, M. A. Influence of topotactic reduction on the structure and magnetism of the multiferroic YMnO3. Chem. Mater. 21, 4940–4948 (2009).
Griffin, S. M., Reidulff, M., Selbach, S. M. & Spaldin, N. A. Defect chemistry as a crystal structure design parameter: intrinsic point defects and Ga substitution in InMnO3. Chem. Mater. 29, 2425–2434 (2017).
Zhang, X., Zhang, Y., Yue, Z. & Zhang, J. Influences of sintering atmosphere on the magnetic and electrical properties of barium hexaferrites. AIP Adv. 9, 085129 (2019).
Keeton, S. C. & Wilson, W. D. Vacancies, interstitials, and rare gases in fluorite structures. Phys. Rev. B 7, 834–843 (1973).
Boulahya, K., Muñoz-Gil, D., Gómez-Herrero, A., Azcondo, M. T. & Amador, U. Eu2SrCo1.5Fe0.5O7 a new promising Ruddlesden–Popper member as a cathode component for intermediate temperature solid oxide fuel cells. J. Mater. Chem. A 7, 5601–5611 (2019).
Yan, Z. et al. Growth of high-quality hexagonal ErMnO3 single crystals by the pressurized floating-zone method. J. Cryst. Growth 409, 75–79 (2015).
Jones, L. et al. Smart Align—a new tool for robust non-rigid registration of scanning microscope data. Adv. Struct. Chem. Imag. 1, 8 (2015).
Nord, M., Vullum, P. E., MacLaren, I., Tybell, T. & Holmestad, R. Atomap: a new software tool for the automated analysis of atomic resolution images using two-dimensional Gaussian fitting. Adv. Struct. Chem. Imag. 3, 9 (2017).
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).
Medvedeva, J. E., Anisimov, V. I., Korotin, M. A., Mryasov, O. N. & Freeman, A. J. Effect of Coulomb correlation and magnetic ordering on the electronic structure of two hexagonal phases of ferroelectromagnetic YMnO3. J. Phys. Condens. Matter 12, 4947–4958 (2001).
Gibbs, A. S., Knight, K. S. & Lightfoot, P. High-temperature phase transitions of hexagonal YMnO3. Phys. Rev. B 83, 94111 (2011).
Degenhardt, C., Fiebig, M., Fröhlich, D., Lottermoser, T. & Pisarev, R. V. V. Nonlinear optical spectroscopy of electronic transitions in hexagonal manganites. Appl. Phys. B 73, 139–144 (2001).
Perdew, J. P. et al. Restoring the density-gradient expansion for exchange in solids and surfaces. Phys. Rev. Lett. 100, 136406 (2008).
Dudarev, S. L., Botton, G. A., Savrasov, S. Y., Humphreys, C. J. & Sutton, A. P. Electron-energy-loss spectra and the structural stability of nickel oxide: an LSDA+U study. Phys. Rev. B 57, 1505–1509 (1998).
Murphy, S. T. & Hine, N. D. M. Anisotropic charge screening and supercell size convergence of defect formation energies. Phys. Rev. B 87, 94111 (2013).
Rehr, J. J. et al. Ab initio theory and calculations of X-ray spectra. C.R. Phys. 10, 548–559 (2009).
We thank T. Grande for fruitful discussions. D.R.S. and S.M.S. were supported by the Research Council of Norway (project no. 231430/F20 and 275139) and acknowledge UNINETT Sigma2 (project no. NN9264K and ntnu243) for providing the computational resources. A.B.M. was supported by NTNU’s Enabling technologies: Nanotechnology. The Research Council of Norway is acknowledged for the support to the Norwegian Micro- and Nano-Fabrication Facility, NorFab, project no. 245963/F50 and Norwegian Centre for Transmission Electron Microscopy, NORTEM, Grant no. 197405. A.L.D. was funded by the Norwegian Research Council under project no. 274459 Translate. K.S. acknowledges the support of the European Research Council under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 724529), Ministerio de Economia, Industria y Competitividad through grant nos. MAT2016-77100-C2-2-P and SEV-2015-0496, and the Generalitat de Catalunya (grant no. 2017SGR 1506). Z.Y. and E.B. were supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division under contract no. DE-AC02-05-CH11231 within the Quantum Materials program KC2202. J.A. was supported by the Academy of Finland under project no. 322832. D.M. thanks NTNU for support through the Onsager Fellowship Programme and NTNU Stjerneprogrammet.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Evans, D.M., Holstad, T.S., Mosberg, A.B. et al. Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide. Nat. Mater. 19, 1195–1200 (2020). https://doi.org/10.1038/s41563-020-0765-x
This article is cited by
Nature Materials (2022)
Nature Reviews Materials (2021)
Nature Materials (2020)