Ferroelectrics and multiferroics

  • Article
    | Open Access

    While magnetism, hyperferroelectricity, and topological phases in the two-dimensional limit have been widely explored, the direct experimental study on bulk photovoltaic effect in 2D materials remains unimplemented. Here, the authors find bulk photovoltaic effect in 2D ferroelectric CuInP2S6.

    • Yue Li
    • , Jun Fu
    •  & Hualing Zeng
  • Article
    | Open Access

    An interest arises if energetic molecules and molecular ferroelectrics can be integrated together to obtain a chemically driven electricity conversion. Here, the authors explore energetic molecular ferroelectrics consisting of imidazolium cations and perchlorate anions with a high-power density.

    • Yong Hu
    • , Zhiyu Liu
    •  & Shenqiang Ren
  • Article
    | Open Access

    Toroidal moments arise from vortex like spin arrangements. These moments can then interact, giving rise to ferri- or ferro-toroidal order, though controlling such order is difficult. Here, the authors demonstrate a ferri-toroidal state in BaCoSiO4, which under an applied magnetic field exhibits multiple toroidal and metamagnetic transitions.

    • Lei Ding
    • , Xianghan Xu
    •  & Huibo Cao
  • Article
    | Open Access

    Phase transition brings a plethora of exotic phenomena and intriguing effects such as spin and charge frustration. However, the phase transition order is not always explicit. Here, the authors discover phase transition frustration near a tricritical composition point in ferroelectric Pb(Zr,Ti)O3.

    • Xian-Kui Wei
    • , Sergei Prokhorenko
    •  & Zuo-Guang Ye
  • Article
    | Open Access

    Free carriers and electrical polarization coexist in ferroelectric metals. Here, the authors use a capacitive method to probe the electronic compressibility of free carriers in a tunable semimetal, extract the polarized contribution, and study the carrier dependence of the ferroelectric state.

    • Sergio C. de la Barrera
    • , Qingrui Cao
    •  & Benjamin M. Hunt
  • Article
    | Open Access

    The majority of polar structures emerging naturally in ferroelectrics are topologically trivial. Here, the authors demonstrate reconstruction of topologically trivial strip-like domain architecture into arrays of polar vortex in (PbTiO3)10/(SrTiO3)10 superlattice.

    • Congbing Tan
    • , Yongqi Dong
    •  & Jiangyu Li
  • Article
    | Open Access

    Compared to inorganic materials, the magnetoelectric coupling in macromolecules is still hidden. Here, the authors describe machine learning coupled with additive manufacturing to accelerate the discovery of multiferroic macromolecules with a proton-mediated magnetoelectric coupling effect.

    • Yong Hu
    • , Scott Broderick
    •  & Shenqiang Ren
  • Article
    | Open Access

    Ferroelectricity in orthoferrite perovskites has stimulated intense research, but the mechanism remains unclear. Here, the authors propose an antisite defect mechanism for introducing ferroelectricity in magnetically ordered YFeO3 and the family of rare earth orthoferrites.

    • Shuai Ning
    • , Abinash Kumar
    •  & Caroline A. Ross
  • Article
    | Open Access

    The observation of negative capacitance effect is focused on the ferroelectrics, while the antiferroelectrics based on Landau switches may have negative capacitance effect. Here, the authors report the static and transient negative capacitance effect in antiferroelectric PbZrO3 and reveal its origin.

    • Leilei Qiao
    • , Cheng Song
    •  & Feng Pan
  • Article
    | Open Access

    Conductive domain walls have been usually found in ferroelectric oxides. Here, the authors report on giant conductivity of domain walls and their magnetically avalanche-like expulsion event in non-oxide ferroelectric GaV4S8, extending the source of phenomena beyond the realm of oxide electronics.

    • S. Ghara
    • , K. Geirhos
    •  & I. Kézsmárki
  • Article
    | Open Access

    Ferroelasticity is predicted theoretically in 2D materials, but it lacks experimental validation. Here, the authors find 2D ferroelasticity in both exfoliated and CVD-grown β’-In2Se3 down to few-layer thickness by atomic-resolution electron microscopy, in situ X-ray diffraction, and polarized-light microscopy.

    • Chao Xu
    • , Jianfeng Mao
    •  & Ye Zhu
  • Article
    | Open Access

    Experimentally manipulating bubble domains remains elusive especially in the bulk form of ferroelectrics. Here, the authors achieve self-confined bubble domains with multiple polar topologies in bulk Bi0.5Na0.5TiO3 ferroelectrics, demonstrating reversible and donut-like domain morphology evolution.

    • Jie Yin
    • , Hongxiang Zong
    •  & Stephen J. Pennycook
  • Article
    | Open Access

    The intrinsic efficiency of electrocaloric materials has been largely overlooked. Here, the authors use the parameter materials efficiency as the figure of merit to rank caloric materials, reporting on the materials efficiency of highly ordered bulk lead scandium tantalate PST.

    • Youri Nouchokgwe
    • , Pierre Lheritier
    •  & Emmanuel Defay
  • Article
    | Open Access

    Domains and domain walls can have distinctively different physical properties. Here, the authors show how to transfer domains into domain walls and vice versa while maintaining their physical properties. Thereby the authors tune a multiferroic state between three and two dimensions.

    • E. Hassanpour
    • , M. C. Weber
    •  & M. Fiebig
  • Article
    | Open Access

    In this work, Meisenheimer et al. use careful epitaxial growth of FeGa thin films to achieve a metastable state with remarkably high magetostrictive coefficients. Materials with strong magnetostrictive properties are vital components in magnetoelectric multiferroic heterostructures, with considerable potential for use a variety of technologies.

    • P. B. Meisenheimer
    • , R. A. Steinhardt
    •  & J. T. Heron
  • Article
    | Open Access

    Space charges or injected charges dominate the ferroelectric degradation, however, its physics insight remains unclear. Here, the authors reveal the nature of ferroelectric degradation in nanodevices and the role of the injected charges in polarization reversal.

    • Qianwei Huang
    • , Zibin Chen
    •  & Xiaozhou Liao
  • Article
    | Open Access

    While the role of PbTiO3 in PbTiO3/SrTiO3 superlattices has been widely studied, little attention is paid to possible polar topologies in SrTiO3. Here, the authors create atomic-scale vortex–antivortex pairs in the superlattices, expanding the understanding of topological structures.

    • Adeel Y. Abid
    • , Yuanwei Sun
    •  & Peng Gao
  • Article
    | Open Access

    There is an ongoing debate in the origin of unusual bumps in the resistive Hall measurements in SrRuO3 systems. Here, the authors analyze surface inversion symmetry breaking and confirm the role of an interfacial Dzyaloshinskii–Moriya interaction at the heart of the system, revealing a magnetic spin crystal emergent across the unusual bumps.

    • S. D. Seddon
    • , D. E. Dogaru
    •  & M. Alexe
  • Article
    | Open Access

    The mechanism for the enhanced piezoelectricity in (K,Na)NbO3 based ceramics has not been fully understood. Here, the authors find that the dopants induced tetragonal phase and the accompanying high-density nanoscale heterostructures are responsible for the high dielectric and piezoelectric properties.

    • Xiaoyi Gao
    • , Zhenxiang Cheng
    •  & Shujun Zhang
  • Article
    | Open Access

    Designing energy efficient and fast optoelectric neuromorphic systems remains a challenge. Long et al. report that the combined optical-electric stimulus enables switching the ferroelectric polarization and cycling the resistance state of BaTiO3 tunnel barriers, showing that the optical control of resistance is non-volatile.

    • Xiao Long
    • , Huan Tan
    •  & Josep Fontcuberta
  • Article
    | Open Access

    While classical approaches rely on the study of individual ferroelectric domain wall movement on long time scales, the authors consider collective movements of domain walls during short time scales, characterized by discrete jumps, as indicators of avalanches on a broad range of scales.

    • Blai Casals
    • , Guillaume F. Nataf
    •  & Ekhard K. H. Salje
  • Article
    | Open Access

    Here, moiré superlattices generated by twisted insulating crystals of hexagonal boron nitride are shown to have a ferroelectric-like character, attributed to strain-induced polarized dipoles formed by pairs of interfacial boron and nitrogen atoms that create bilayer-thick ferroelectric domains.

    • C. R. Woods
    • , P. Ares
    •  & L. Fumagalli
  • Article
    | Open Access

    CO2 is a problematic greenhouse gas, although its conversion to alternative fuels represents a promising approach to limit its long-term effects. Here, the authors demonstrate that CO2 can be reduced to methanol through pyroelectric catalysis under temperature variation near room temperature.

    • Lingbo Xiao
    • , Xiaoli Xu
    •  & Guifu Zou
  • Article
    | Open Access

    The authors study the evolution of the bulk photovoltaic effect in BiFeO3 thin films with stripe-domains as the polarization of light is modulated from linear to circular. A relationship between the anomalous photo-response and differential light-domain interaction is established.

    • David S. Knoche
    • , Matthias Steimecke
    •  & Akash Bhatnagar
  • Article
    | Open Access

    Ferroelectric domain wall profiles can be modeled by phenomenological Ginzburg-Landau theory, with different candidate models and parameters. Here, the authors solve the problem of model selection by developing a Bayesian inference framework allowing for uncertainty quantification and apply it to atomically resolved images of walls. This analysis can also predict the level of microscope performance needed to detect specific physical phenomena.

    • Christopher T. Nelson
    • , Rama K. Vasudevan
    •  & Sergei V. Kalinin
  • Article
    | Open Access

    How to maintain a robust polarization in ferroelectrics despite its inherent suppression when going to the thin-film limit is a long-standing issue. Here, the authors propose the concept of competitive and cooperative interfaces and establish robust polarization states in the ultrathin regime.

    • Nives Strkalj
    • , Chiara Gattinoni
    •  & Morgan Trassin
  • Article
    | Open Access

    Understanding the processes underlying the self-assembly of polar textures is pivotal for the development of future technologies. Here, the authors reveal the dynamics of nonequilibrium phase transitions in low-dimensional ferroelectrics and emphasize their topological nature.

    • Y. Nahas
    • , S. Prokhorenko
    •  & L. Bellaiche
  • Article
    | Open Access

    Understanding the underlying physics and improving the performance of mixed lead halide perovskite materials remains a challenge. Here, the authors present experimental and theoretical study of structural phases, phase transitions, and dipolar dynamics in the mixed cation MA1-xDMAxPbBr3 perovskites.

    • Mantas Simenas
    • , Sergejus Balciunas
    •  & Juras Banys
  • Article
    | Open Access

    A room temperature single-phase multiferroic with large and strongly coupled polarization and magnetization is a long-sought goal in multiferroics research. Here, the authors predict a promising candidate, layered-perovskite metal Bi5Mn5O17, which is a ferromagnet, ferroelectric, and ferrotoroid.

    • Andrea Urru
    • , Francesco Ricci
    •  & Vincenzo Fiorentini
  • Article
    | Open Access

    Observation of a strain-gradient-induced piezoresponse at domain walls remains a challenge. Here, the authors find the piezoelectric response to be enhanced in the ferroelastic domain walls of centrosymmetric tungsten trioxide thin films due to a large strain gradient over a wide width of the wall.

    • Shinhee Yun
    • , Kyung Song
    •  & Chan-Ho Yang
  • Article
    | Open Access

    Superconductivity in doped SrTiO3 near to a ferroelectric quantum critical point emerges due to a strong interaction driving the formation of Cooper pairs, the nature of which has remained elusive for several decades.  Here, the authors reveal that pairing is due to the exchange of longitudinal hybrid polar modes rather than transverse critical modes.

    • C. Enderlein
    • , J. Ferreira de Oliveira
    •  & S. E. Rowley
  • Article
    | Open Access

    Dielectric capacitors are widely used in electronic systems but they possess inferior energy density in comparison with other electrochemical energy storage. Here, the authors construct a diffused phase boundary to simultaneously achieve high energy storage density and efficiency in AgNbO3antiferroelectrics.

    • Nengneng Luo
    • , Kai Han
    •  & Yuezhou Wei
  • Article
    | Open Access

    Despite the apparent simplicity of a H2O molecule, the mutual ferroelectric ordering of the molecules is unresolved. Here, the authors realize a macroscopic ferroelectric phase transition in a network of dipole-dipole coupled water molecules located in nanopores of gemstone.

    • M. A. Belyanchikov
    • , M. Savinov
    •  & B. Gorshunov
  • Article
    | Open Access

    The large family PbZrO3-based solid solutions are usually considered as antiferroelectric materials with specific antiparallel polarization configuration. Here, the authors demonstrate the PbZrO3-based material has ferrielectric dipoles ordering and configure a clear structure-property relationship.

    • Zhengqian Fu
    • , Xuefeng Chen
    •  & Fangfang Xu
  • Article
    | Open Access

    Domain walls in van der Waals layered ferrielectric CuInP2Se6 exhibit piezoelectric response. This striking departure from traditional ferroelectric behavior is ascribed to a partially polarized antiferroelectric state, where the domain wall separates coexisting regions of ferrielectric and antiferroelectric phases.

    • Andrius Dziaugys
    • , Kyle Kelley
    •  & Petro Maksymovych