Cohen, R. E. Origin of ferroelectricity in perovskite oxides. Nature 358, 136â138 (1992).
Zhong, W., King-Smith, R. D. & Vanderbilt, D. Giant LO-TO splittings in perovskite ferroelectrics. Phys. Rev. Lett. 72, 3618â3621 (1994).
Junquera, J. & Ghosez, P. Critical thickness for ferroelectricity in perovskite ultrathin films. Nature 422, 506â509 (2003).
Stengel, M. & Spaldin, N. A. Origin of the dielectric dead layer in nanoscale capacitors. Nature 443, 679â682 (2006).
Yim, K. et al. Novel high-κ dielectrics for next-generation electronic devices screened by automated ab initio calculations. NPG Asia Mater. 7, e190âe190 (2015).
Cheema, S. S. et al. Emergent ferroelectricity in subnanometer binary oxide films on silicon. Science 376, 648â652 (2022).
Cheema, S. S. et al. Enhanced ferroelectricity in ultrathin films grown directly on silicon. Nature 580, 478â482 (2020).
Bousquet, E., Spaldin, N. A. & Ghosez, P. Strain-induced ferroelectricity in simple rocksalt binary oxides. Phys. Rev. Lett. 104, 037601 (2010).
Li, C. W. et al. Orbitally driven giant phonon anharmonicity in SnSe. Nat. Phys. 11, 1063â1069 (2015).
Shportko, K. et al. Resonant bonding in crystalline phase-change materials. Nat. Mater. 7, 653â658 (2008).
Robertson, J. High dielectric constant oxides. Eur. Phys. J. Appl. Phys. 28, 265â291 (2004).
Delaire, O. et al. Giant anharmonic phonon scattering in PbTe. Nat. Mater. 10, 614â619 (2011).
Lee, S. et al. Resonant bonding leads to low lattice thermal conductivity. Nat. Commun. 5, 3525 (2014).
Ghosez, P., Michenaud, J.-P. & Gonze, X. Dynamical atomic charges: the case of ABO3 compounds. Phys. Rev. B 58, 6224â6240 (1998).
Cochran, W. Crystal stability and the theory of ferroelectricity. Phys. Rev. Lett. 3, 412â414 (1959).
Axe, J. D. Apparent ionic charges and vibrational eigenmodes of BaTiO3 and other perovskites. Phys. Rev. 157, 429â435 (1967).
Sirenko, A. A. et al. Soft-mode hardening in SrTiO3 thin films. Nature 404, 373â376 (2000).
Kang, S. et al. Highly enhanced ferroelectricity in HfO2-based ferroelectric thin film by light ion bombardment. Science 376, 731â738 (2022).
Kalinin, S. V., Kim, Y., Fong, D. D. & Morozovska, A. N. Surface-screening mechanisms in ferroelectric thin films and their effect on polarization dynamics and domain structures. Rep. Prog. Phys. 81, 036502 (2018).
Lee, D. et al. Emergence of room-temperature ferroelectricity at reduced dimensions. Science 349, 1314â1317 (2015).
Ahn, C. H., Rabe, K. M. & Triscone, J.-M. Ferroelectricity at the nanoscale: local polarization in oxide thin films and heterostructures. Science 303, 488â491 (2004).
Noheda, B. & Ãñiguez, J. A key piece of the ferroelectric hafnia puzzle. Science 369, 1300â1301 (2020).
Warusawithana, M. P. et al. A ferroelectric oxide made directly on silicon. Science 324, 367â370 (2009).
Cheema, S. S. et al. Ultrathin ferroic HfO2âZrO2 superlattice gate stack for advanced transistors. Nature 604, 65â71 (2022).
Harrison, W. A. Elementary Electronic Structure (World Scientific, 1999).
Rabe, K. M., Ahn, C. H. & Triscone, J. Physics of Ferroelectrics: A Modern Perspective (Springer, 2007).
Pauling, L. The size of ions and the structure of ionic crystals. J. Am. Chem. Soc. 49, 765â790 (1927).
Shannon, R. D. & Prewitt, C. T. Effective ionic radii in oxides and fluorides. Acta Crystallogr. B Struct. Sci. 25, 925â946 (1969).
Haeni, J. H. et al. Room-temperature ferroelectricity in strained SrTiO3. Nature 430, 758â761 (2004).
Hatt, A. J., Spaldin, N. A. & Ederer, C. Strain-induced isosymmetric phase transition in BiFeO3. Phys. Rev. B 81, 054109 (2010).
Iwazaki, Y., Suzuki, T., Mizuno, Y. & Tsuneyuki, S. Doping-induced phase transitions in ferroelectric BaTiO3 from first-principles calculations. Phys. Rev. B 86, 214103 (2012).
Moriwake, H. et al. The electric field induced ferroelectric phase transition of AgNbO3. J. Appl. Phys. 119, 064102 (2016).
Van Aken, B. B., Palstra, T. T. M., Filippetti, A. & Spaldin, N. A. The origin of ferroelectricity in magnetoelectric YMnO3. Nat. Mater. 3, 164â170 (2004).
Greaves, G. N., Greer, A. L., Lakes, R. S. & Rouxel, T. Poissonâs ratio and modern materials. Nat. Mater. 10, 823â837 (2011).
Reyes-Lillo, S. E., Garrity, K. F. & Rabe, K. M. Antiferroelectricity in thin-film ZrO2 from first principles. Phys. Rev. B 90, 140103 (2014).
Raeliarijaona, A. & Cohen, R. E. Hafnia HfO2 is a proper ferroelectric. Phys. Rev. B 108, 094109 (2023).
Lee, H.-J. et al. Scale-free ferroelectricity induced by flat phonon bands in HfO2. Science 369, 1343â1347 (2020).
Zhou, S., Zhang, J. & Rappe, A. M. Strain-induced antipolar phase in hafnia stabilizes robust thin-film ferroelectricity. Sci. Adv. 8, eadd5953 (2022).
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953â17979 (1994).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169â11186 (1996).
Ceperley, D. M. & Alder, B. J. Ground state of the electron gas by a stochastic method. Phys. Rev. Lett. 45, 566â569 (1980).
Bernardini, F. & Fiorentini, V. Electronic dielectric constants of insulators calculated by the polarization method. Phys. Rev. B 58, 15292â15295 (1998).
Baroni, S., Giannozzi, P. & Testa, A. Greenâs-function approach to linear response in solids. Phys. Rev. Lett. 58, 1861â1864 (1987).
Gonze, X. First-principles responses of solids to atomic displacements and homogeneous electric fields: Implementation of a conjugate-gradient algorithm. Phys. Rev. B 55, 10337â10354 (1997).
Gonze, X. & Lee, C. Dynamical matrices, Born effective charges, dielectric permittivity tensors, and interatomic force constants from density-functional perturbation theory. Phys. Rev. B 55, 10355â10368 (1997).
Giannozzi, P., de Gironcoli, S., Pavone, P. & Baroni, S. Ab initio calculation of phonon dispersions in semiconductors. Phys. Rev. B 43, 7231â7242 (1991).
Waghmare, U. V. & Rabe, K. M. Ab initio statistical mechanics of the ferroelectric phase transition in PbTiO3. Phys. Rev. B 55, 6161â6173 (1997).
Esfarjani, K. & Stokes, H. T. Method to extract anharmonic force constants from first principles calculations. Phys. Rev. B 77, 144112 (2008).
Togo, A. & Tanaka, I. First principles phonon calculations in materials science. Scr. Mater. 108, 1â5 (2015).
Wang, Z.-H., Zhang, X. & Wei, S.-H. Origin of structural anomaly in cuprous halides. J. Phys. Chem. Lett. 13, 11438â11443 (2022).
Zhang, Y., Liu, M., Wang, J., Shimada, T. & Kitamura, T. Strain tunable ferroelectric and dielectric properties of BaZrO3. J. Appl. Phys. 115, 224107 (2014).
Toulouse, C. et al. Lattice dynamics and Raman spectrum of BaZrO3 single crystals. Phys. Rev. B 100, 134102 (2019).
Xie, L. & Zhu, J. The electronic structures, Born effective charges, and interatomic force constants in BaMO3 (Mâ=âTi, Zr, Hf, Sn): a comparative firstâprinciples study. J. Am. Ceram. Soc. 95, 3597â3604 (2012).
Zhang, Y., Wang, J., Sahoo, M. P. K., Shimada, T. & Kitamura, T. Strain-induced ferroelectricity and lattice coupling in BaSnO3 and SrSnO3. Phys. Chem. Chem. Phys. 19, 26047â26055 (2017).
Stengel, M., Vanderbilt, D. & Spaldin, N. A. Enhancement of ferroelectricity at metalâoxide interfaces. Nat. Mater. 8, 392â397 (2009).
Zhang, Y., Li, G.-P., Shimada, T., Wang, J. & Kitamura, T. Disappearance of ferroelectric critical thickness in epitaxial ultrathin BaZrO3 films. Phys. Rev. B 90, 184107 (2014).
Ramesh, R. & Spaldin, N. A. Multiferroics: progress and prospects in thin films. Nat. Mater. 6, 21â29 (2007).
Fan, S. et al. Vibrational fingerprints of ferroelectric HfO2. npj Quantum Mater. 7, 32 (2022).
Sternik, M. & Parlinski, K. Lattice vibrations in cubic, tetragonal, and monoclinic phases of ZrO2. J. Chem. Phys. 122, 064707 (2005).
Cao, R. et al. Data for âSoftening of the optical phonon by reduced interatomic bonding strength without depolarizationâ. Figshare https://doi.org/10.6084/m9.figshare.26826472 (2024).
Hill, N. A. Why are there so few magnetic ferroelectrics? J. Phys. Chem. B 104, 6694â6709 (2000).
Rondinelli, J. M., Eidelson, A. S. & Spaldin, N. A. Non-d0 Mn-driven ferroelectricity in antiferromagnetic BaMnO3. Phys. Rev. B 79, 205119 (2009).
Qin, G. et al. Resonant bonding driven giant phonon anharmonicity and low thermal conductivity of phosphorene. Phys. Rev. B 94, 165445 (2016).
Ghosez, P., Cockayne, E., Waghmare, U. V. & Rabe, K. M. Lattice dynamics of BaTiO3, PbTiO3, and PbZrO3: a comparative first-principles study. Phys. Rev. B 60, 836â843 (1999).
Crema, A. P. S. et al. Ferroelectric orthorhombic ZrO2 thin films achieved through nanosecond laser annealing. Adv. Sci. 10, 2207390 (2023).
Huang, K.-W. et al. Sub-7-nm textured ZrO2 with giant ferroelectricity. Acta Mater. 205, 116536 (2021).
Chae, K. et al. Local epitaxial templating effects in ferroelectric and antiferroelectric ZrO2. ACS Appl. Mater. Interfaces 14, 36771â36780 (2022).
Xu, B., Lomenzo, P. D., Kersch, A., Mikolajick, T. & Schroeder, U. Influence of Si-doping on 45ânm thick ferroelectric ZrO2 films. ACS Appl. Electron. Mater. 4, 3648â3654 (2022).
Starschich, S., Schenk, T., Schroeder, U. & Boettger, U. Ferroelectric and piezoelectric properties of Hf1-xZrxO2 and pure ZrO2 films. Appl. Phys. Lett. 110, 182905 (2017).
Wu, Y. et al. Unconventional polarization-switching mechanism in (Hf,Zr)O2 ferroelectrics and its implications. Phys. Rev. Lett. 131, 226802 (2023).
