Scott, J. F. Applications of modern ferroelectrics. Science 315, 954–959 (2007).
Google Scholar
Guo, R. et al. Non-volatile memory based on the ferroelectric photovoltaic effect. Nat. Commun. 4, 1990 (2013).
Google Scholar
Dawber, M., Rabe, K. M. & Scott, J. F. Physics of thin-film ferroelectric oxides. Rev. Mod. Phys. 77, 1083 (2005).
Google Scholar
Qiao, H., Wang, C., Choi, W. S., Park, M. H. & Kim, Y. Ultra-thin ferroelectrics. Mater. Sci. Eng. R Rep. 145, 100622 (2021).
Google Scholar
Kim, K.-E. et al. Configurable topological textures in strain graded ferroelectric nanoplates. Nat. Commun. 9, 403 (2018).
Google Scholar
Li, Y. L., Hu, S. Y., Liu, Z. K. & Chen, L.-Q. Effect of electrical boundary conditions on ferroelectric domain structures in thin films. Appl. Phys. Lett. 81, 427–429 (2002).
Google Scholar
Feigl, L. et al. Controlled stripes of ultrafine ferroelectric domains. Nat. Commun. 5, 4677 (2014).
Google Scholar
Polking, M. J. et al. Ferroelectric order in individual nanometre-scale crystals. Nat. Mater. 11, 700–709 (2012).
Google Scholar
Lee, H.-J. et al. Scale-free ferroelectricity induced by flat phonon bands in HfO2. Science 369, 1343–1347 (2020).
Google Scholar
Benedek, N. A., Rondinelli, J. M., Djani, H., Ghosez, P. & Lightfoot, P. Understanding ferroelectricity in layered perovskites: new ideas and insights from theory and experiments. Dalton Trans. 44, 10543 (2015).
Google Scholar
Oh, Y. S., Luo, X., Huang, F.-T., Wang, Y. & Cheong, S.-W. Experimental demonstration of hybrid improper ferroelectricity and the presence of abundant charged walls in (Ca,Sr)3Ti2O7 crystal. Nat. Mater. 14, 407–413 (2015).
Google Scholar
Guo, Y. et al. Unit-cell-thick domain in free-standing quasi-two-dimensional ferroelectric material. Phys. Rev. Mater. 5, 044403 (2021).
Google Scholar
Han, M. et al. Continuously tunable ferroelectric domain width down to the single-atomic limit in bismuth tellurite. Nat. Comm. 13, 5903 (2022).
Google Scholar
Mitra, C., Meyer, T., Lee, H. N. & Reboredo, F. A. Oxygen diffusion pathways in brownmillerite SrCoO2.5: influence of structure and chemical potential. J. Chem. Phys. 141, 084710 (2014).
Google Scholar
Fuller, C. A. et al. Brownmillerite-type Sr2ScGaO5 oxide ion conductor: local structure, phase transition, and dynamics. Chem. Mater. 31, 7395–7404 (2019).
Google Scholar
Lim, J. S. et al. Harnessing the topotactic transition in oxide heterostructures for fast and high-efficiency electrochromic applications. Sci. Adv. 6, eabb8553 (2020).
Google Scholar
Choi, W. S. et al. Reversal of the lattice structure in SrCoOx epitaxial thin films studied by real-time optical spectroscopy and first-principles calculations. Phys. Rev. Lett. 111, 097401 (2013).
Google Scholar
Lee, J. H. et al. Strongly coupled magnetic and electronic transitions in multivalent strontium cobaltites. Sci. Rep. 7, 16066 (2017).
Google Scholar
Auckett, J. E. et al. Combined experimental and computational study of oxide ion conduction dynamics in Sr2Fe2O5 brownmillerite. Chem. Mater. 25, 3080–3087 (2013).
Google Scholar
Jeen, H. et al. Topotactic phase transformation of the brownmillerite SrCoO2.5 to the perovskite SrCoO3–δ. Adv. Mater. 25, 3651–3656 (2013).
Google Scholar
Jeen, H. et al. Reversible redox reactions in an epitaxially stabilized SrCoOx oxygen sponge. Nat. Mater. 12, 1057–1063 (2013).
Google Scholar
Khare, A. et al. Topotactic metal–insulator transition in epitaxial SrFeOx thin films. Adv. Mater. 29, 1606566 (2017).
Google Scholar
Young, J. & Rondinelli, J. M. Crystal structure and electronic properties of bulk and thin film brownmillerite oxides. Phys. Rev. B 92, 174111 (2015).
Google Scholar
Lim, J. & Yu, J. Role of oxygen vacancy in the spin-state change and magnetic ordering in SrCoO3−δ. Phys. Rev. B 98, 085106 (2018).
Google Scholar
Kang, K. T. et al. A room-temperature ferroelectric ferromagnet in a 1D tetrahedral chain network. Adv. Mater. 31, 1808104 (2019).
Google Scholar
Tian, H. et al. Novel type of ferroelectricity in brownmillerite structures: a first-principles study. Phys. Rev. Mater. 2, 084402 (2018).
Google Scholar
Heifets, E., Kotomin, E. A., Bagaturyants, A. A. & Maier, J. Thermodynamic stability of non-stoichiometric SrFeO3−δ: a hybrid DFT study. Phys. Chem. Chem. Phys. 21, 3918–3931 (2019).
Google Scholar
Inoue, S. et al. Anisotropic oxygen diffusion at low temperature in perovskite-structure iron oxides. Nat. Chem. 2, 213–217 (2010).
Google Scholar
Khare, A. et al. Directing oxygen vacancy channels in SrFeO2.5 epitaxial thin films. ACS Appl. Mater. Interfaces 10, 4831–4837 (2018).
Google Scholar
Bilc, D. I. et al. Hybrid exchange-correlation functional for accurate prediction of the electronic and structural properties of ferroelectric oxides. Phys. Rev. B 77, 165107 (2008).
Google Scholar
Kim, J. R. et al. Stabilizing hidden room-temperature ferroelectricity via a metastable atomic distortion pattern. Nat. Commun. 11, 4944 (2020).
Google Scholar
Han, M.-G. et al. Interface-induced nonswitchable domains in ferroelectric thin films. Nat. Commun. 5, 4693 (2014).
Google Scholar
Kim, Y., Choi, Y., Lee, S. A., Choi, W. S., & Kang, K. T. Complex oxide thin films: a review on pulsed laser epitaxy growth. Curr. Appl. Phys. 64, 113–130 (2024).
Han, J., Go, K.-J., Jang, J., Yang, S. & Choi, S.-Y. Materials property mapping from atomic scale imaging via machine learning based sub-pixel processing. npj Comput. Mater. 8, 196 (2022).
Google Scholar
Barthel, J. Dr. Probe: a software for high-resolution STEM image simulation. Ultramicroscopy 193, 1–11 (2018).
Google Scholar
Perdew, J. P., Burke, K. & Wang, Y. Generalized gradient approximation for the exchange-correlation hole of a many-electron system. Phys. Rev. B 54, 16533–16539 (1996).
Google Scholar
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).
Google Scholar
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).
Google Scholar
Henkelman, G., Uberuaga, B. P. & Jónsson, H. A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J. Chem. Phys. 113, 9901–9904 (2000).
Google Scholar
King-Smith, R. D. & Vanderbilt, D. Theory of polarization of crystalline solids. Phys. Rev. B 47, 1651–1654 (1993).
Google Scholar
Togo, A., Oba, F. & Tanaka, I. First-principles calculations of the ferroelastic transition between rutile-type and CaCl2-type SiO2 at high pressures. Phys. Rev. B 78, 134106 (2008).
Google Scholar
