1
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Kashikar R, Valdespino A, Ogg C, Uppgard E, Lisenkov S, Ponomareva I. Ferroelectricity in Ultrathin Halide Perovskites. NANO LETTERS 2024. [PMID: 39140493 DOI: 10.1021/acs.nanolett.4c02940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Ferroelectricity has recently been demonstrated in germanium-based halide perovskites. We use first-principles-based simulations to study 4-18 nm CsGeBr3 films and develop a theory for ferroelectric ultrathin films. The theory introduces (i) a local order parameter, which identifies phase transitions into both monodomain and polydomain phases, and (ii) a dipole pattern classifier, which allows efficient and reliable identification of dipole patterns. Application of the theory to both halides CsGeBr3 and CsGeI3 and oxide BiFeO3 ultrathin ferroelectrics reveals two distinct scenarios. First, the films transition into a monodomain phase below the critical value of the residual depolarizing field. Above this critical value, the second scenario occurs, and the film undergoes a transition into a nanodomain phase. The two scenarios exhibit opposite responses of Curie temperature to thickness reduction. Application of a dipole pattern classifier reveals rich nanodomain phases in halide films: nanostripes, labyrinths, zig-zags, pillars, and lego domains.
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Affiliation(s)
- Ravi Kashikar
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Arlies Valdespino
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Charlton Ogg
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Edvin Uppgard
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - S Lisenkov
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - I Ponomareva
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
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2
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Xu S, Wang X, Bellaiche L, Xu B. Electric Control of Magnetism in Multiferroic Rare-Earth-Substituted BiFeO_{3} with Ferrielectricity. PHYSICAL REVIEW LETTERS 2024; 133:046801. [PMID: 39121429 DOI: 10.1103/physrevlett.133.046801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 04/23/2024] [Accepted: 06/05/2024] [Indexed: 08/11/2024]
Abstract
The multiferroic rare-earth-substituted BiFeO_{3} has emerged as a promising candidate to achieve ultralow-energy-dissipation logic or memory devices, but the fundamental details of the switching mechanism involving the electrical, structural, and magnetic degrees of freedom is not fully understood, in particular, in its single-phase form. Here, a first-principles-based computational scheme is used to study Nd-doped BiFeO_{3} as a model system. The structure that yields a reduced P-E hysteresis loop is found to be ferrielectric with modulated octahedral tiltings, and it is shown that both the in-plane and out-of-plane ferromagnetization can be controlled by an applied electric field. The switching behaviors can be well interpreted by a Landau-type model, in which the magnetoelectric coupling is indirect and mediated by octahedral tiltings. The effects of varied composition and temperature are further discussed, revealing important correlations between the polarization switching and the robustness of the control of magnetization.
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Affiliation(s)
- Shiji Xu
- Jiangsu Key Laboratory of Frontier Material Physics and Devices, Institute of Theoretical and Applied Physics, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Xin Wang
- Jiangsu Key Laboratory of Frontier Material Physics and Devices, Institute of Theoretical and Applied Physics, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - L Bellaiche
- Smart Ferroic Materials Center, Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Department of Materials Science and Engineering, Tel Aviv University, Ramat Aviv, Tel Aviv 6997801, Israel
| | - Bin Xu
- Jiangsu Key Laboratory of Frontier Material Physics and Devices, Institute of Theoretical and Applied Physics, School of Physical Science and Technology, Soochow University, Suzhou 215006, China
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3
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Morais EA, Caturello NAMS, Lemes MA, Ferreira H, Ferreira FF, Acuña JJS, Brochsztain S, Dalpian GM, Souza JA. Rashba Spin Splitting Limiting the Application of 2D Halide Perovskites for UV-Emitting Devices. ACS APPLIED MATERIALS & INTERFACES 2024; 16:4261-4270. [PMID: 38217498 DOI: 10.1021/acsami.3c16541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2024]
Abstract
Layered lead halide perovskites have attracted much attention as promising materials for a new generation of optoelectronic devices. To make progress in applications, a full understanding of the basic properties is essential. Here, we study 2D-layered (BA)2PbX4 by using different halide anions (X = I, Br, and Cl) along with quantum confinement. The obtained cell parameter evolution, supported by experimental measurements and theoretical calculations, indicates strong lattice distortions of the metal halide octahedra, breaking the local inversion symmetry in (BA)2PbCl4, which strongly correlates with a pronounced Rashba spin-splitting effect. Optical measurements reveal strong photoluminescence quenching and a drastic reduction in the PL quantum yield in this larger band gap compound. We suggest that these optical results are closely related to the appearance of the Rashba effect due to the existence of a local electric dipole. The results obtained in ab initio calculations showed that the (BA)2PbCl4 possesses electrical polarization of 0.13 μC/cm2 and spin-splitting energy of about 40 meV. Our work establishes that local octahedra distortions induce Rashba spin splitting, which explains why obtaining UV-emitting materials with high PLQY is a big challenge.
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Affiliation(s)
- Eliane A Morais
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Naidel A M S Caturello
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Maykon A Lemes
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Henrique Ferreira
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Fabio F Ferreira
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Jose J S Acuña
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Sergio Brochsztain
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
| | - Gustavo M Dalpian
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
- Institute of Physics, University of São Paulo, São Paulo, SP 05508-090, Brazil
| | - Jose A Souza
- Center for Natural and Human Sciences (CCNH), Federal University of ABC (UFABC), Santo André, SP 09210-580, Brazil
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4
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Gao L, Prokhorenko S, Nahas Y, Bellaiche L. Dynamical Control of Topology in Polar Skyrmions via Twisted Light. PHYSICAL REVIEW LETTERS 2024; 132:026902. [PMID: 38277608 DOI: 10.1103/physrevlett.132.026902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 09/23/2023] [Accepted: 11/08/2023] [Indexed: 01/28/2024]
Abstract
Twisted light carries a nonzero orbital angular momentum, that can be transferred from light to electrons and particles ranging from nanometers to micrometers. Up to now, the interplay between twisted light with dipolar systems has scarcely been explored, though the latter bear abundant forms of topologies such as skyrmions and embrace strong light-matter coupling. Here, using first-principles-based simulations, we show that twisted light can excite and drive dynamical polar skyrmions and transfer its nonzero winding number to ferroelectric ultrathin films. The skyrmion is successively created and annihilated alternately at the two interfaces, and experiences a periodic transition from a markedly "Bloch" to "Néel" character, accompanied with the emergence of a "Bloch point" topological defect with vanishing polarization. The dynamical evolution of skyrmions is connected to a constant jump of topological number between "0" and "1" over time. These intriguing phenomena are found to have an electrostatic origin. Our study thus demonstrates that, and explains why this unique light-matter interaction can be very powerful in creating and manipulating topological solitons in functional materials.
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Affiliation(s)
- Lingyuan Gao
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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5
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Gao L, Prokhorenko S, Nahas Y, Bellaiche L. Dynamical Multiferroicity and Magnetic Topological Structures Induced by the Orbital Angular Momentum of Light in a Nonmagnetic Material. PHYSICAL REVIEW LETTERS 2023; 131:196801. [PMID: 38000422 DOI: 10.1103/physrevlett.131.196801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 09/19/2023] [Indexed: 11/26/2023]
Abstract
Recent studies have revealed that chiral phonons resonantly excited by ultrafast laser pulses carry magnetic moments and can enhance the magnetization of materials. In this work, using first-principles-based simulations, we present a real-space scenario where circular motions of electric dipoles in ultrathin two-dimensional ferroelectric and nonmagnetic films are driven by orbital angular momentum of light via strong coupling between electric dipoles and optical field. Rotations of these dipoles follow the evolving pattern of the optical field and create strong on-site orbital magnetic moments of ions. By characterizing topology of orbital magnetic moments in each 2D layer, we identify the vortex type of topological texture-magnetic merons with a one-half topological charge and robust stability. Our study thus provides alternative approaches for generating magnetic fields and topological textures from light-matter interaction and dynamical multiferroicity in nonmagnetic materials.
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Affiliation(s)
- Lingyuan Gao
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Sergei Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Yousra Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Laurent Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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6
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Zhang Y, Zhang J, He X, Wang J, Ghosez P. Rare-earth control of phase transitions in infinite-layer nickelates. PNAS NEXUS 2023; 2:pgad108. [PMID: 37181050 PMCID: PMC10167552 DOI: 10.1093/pnasnexus/pgad108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 03/16/2023] [Indexed: 05/16/2023]
Abstract
Perovskite nickelates RNiO3 (R = rare-earth ion) exhibit complex rare-earth ion dependent phase diagram and high tunability of various appealing properties. Here, combining first- and finite-temperature second-principles calculations, we explicitly demonstrate that the superior merits of the interplay among lattice, electron, and spin degrees of freedom can be passed to RNiO2, which recently gained significant interest as superconductors. We unveil that decreasing the rare-earth size directly modulates the structural, electronic, and magnetic properties and naturally groups infinite-layer nickelates into two categories in terms of the Fermi surface and magnetic dimensionality: compounds with large rare-earth sizes (La, Pr) closely resemble the key properties of CaCuO2, showing quasi-two-dimensional (2D) antiferromagnetic (AFM) correlations and strongly localized d x 2 - y 2 orbitals around the Fermi level; the compounds with small rare-earth sizes (Nd-Lu) are highly analogous to ferropnictides, showing three-dimensional (3D) magnetic dimensionality and strong k z dispersion of d 3 z 2 - r 2 electrons at the Fermi level. Additionally, we highlight that RNiO2 with R = Nd-Lu exhibit on cooling a structural transition with the appearance of oxygen rotation motion, which is softened by the reduction of rare-earth size and enhanced by spin-rotation couplings. The rare-earth control of k z dispersion and structural phase transition might be the key factors differentiating the distinct upper critical field and resistivity in different compounds. The established original phase diagram summarizing the temperature and rare-earth controlled structural, electronic, and magnetic transitions in RNiO2 compounds provides rich structural and chemical flexibility to tailor the superconducting property.
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Affiliation(s)
- Yajun Zhang
- Key Laboratory of Mechanics on Disaster and Environment in Western China Attached to The Ministry of Education of China, Lanzhou University, Lanzhou 730000 Gansu, China
- Department of Mechanics and Engineering Science, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000 Gansu, China
| | - Jingtong Zhang
- Theoretical Materials Physics, Q-MAT, CESAM, Université de Liège, B-4000 Liège, Belgium
- Department of Engineering Mechanics and Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
- Zhejiang Laboratory, Hangzhou, 311100 Zhejiang, China
| | - Xu He
- Theoretical Materials Physics, Q-MAT, CESAM, Université de Liège, B-4000 Liège, Belgium
| | - Jie Wang
- Department of Engineering Mechanics and Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
- Zhejiang Laboratory, Hangzhou, 311100 Zhejiang, China
| | - Philippe Ghosez
- Theoretical Materials Physics, Q-MAT, CESAM, Université de Liège, B-4000 Liège, Belgium
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7
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Rafique MD, Gillani SSA. Isotropic pressure-induced electronic band structure of BaTiO 3, SrTiO 3 and CaTiO 3 with its impact on structural and optical properties: ab-initio calculation. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2123944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
| | - S. S. A. Gillani
- Department of Physics, Government College University Lahore, Lahore, Pakistan
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8
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Pressure-driven ferroelectric phase transition for the Pnma-CsPbBr3: Mechanical and dynamical stability study. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Gillani SSA, Ahmed I, Zeba I, Shakil M, Ahmad R. First-principles calculations to investigate structural phase transformation to semi-conductor–metal transition and their impact on optical properties in lead titanium oxynitrate. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2078816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- S. S. A. Gillani
- Department of Physics, Government College University Lahore, Lahore, Pakistan
| | - Iqra Ahmed
- Department of Physics, Government College University Lahore, Lahore, Pakistan
| | - I. Zeba
- Department of Physics, Lahore College for Woman University Lahore, Lahore, Pakistan
| | - M. Shakil
- Department of Physics, University of Gujrat, Gujrat, Pakistan
| | - Riaz Ahmad
- Department of Physics, Government College University Lahore, Lahore, Pakistan
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10
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Ab Initio Computations of O and AO as well as ReO2, WO2 and BO2-Terminated ReO3, WO3, BaTiO3, SrTiO3 and BaZrO3 (001) Surfaces. Symmetry (Basel) 2022. [DOI: 10.3390/sym14051050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We present and discuss the results of surface relaxation and rumpling computations for ReO3, WO3, SrTiO3, BaTiO3 and BaZrO3 (001) surfaces employing a hybrid B3LYP or B3PW description of exchange and correlation. In particular, we perform the first B3LYP computations for O-terminated ReO3 and WO3 (001) surfaces. In most cases, according to our B3LYP or B3PW computations for both surface terminations BO2- and O, AO-terminated ReO3, WO3, BaTiO3, SrTiO3 and BaZrO3 (001) surface upper layer atoms shift downwards, towards the bulk, the second layer atoms shift upwards and the third layer atoms, again, shift downwards. Our ab initio computes that ReO3, WO3, BaTiO3, SrTiO3 and BaZrO3 (001) surface Γ-Γ bandgaps are always smaller than their respective bulk Γ-Γ bandgaps. Our first principles compute that B-O atom chemical bond populations in the BaTiO3, SrTiO3 and BaZrO3 perovskite bulk are always smaller than near their BO2-terminated (001) surfaces. Just opposite, the Re-O and W-O chemical bond populations in the ReO3 (0.212e) and WO3 (0.142e) bulk are slightly larger than near the ReO2 and WO2-terminated ReO3 as well as WO3 (001) surfaces (0.170e and 0.108e, respectively).
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11
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High-density switchable skyrmion-like polar nanodomains integrated on silicon. Nature 2022; 603:63-67. [PMID: 35236971 DOI: 10.1038/s41586-021-04338-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 12/10/2021] [Indexed: 11/08/2022]
Abstract
Topological domains in ferroelectrics1-5 have received much attention recently owing to their novel functionalities and potential applications6,7 in electronic devices. So far, however, such topological polar structures have been observed only in superlattices grown on oxide substrates, which limits their applications in silicon-based electronics. Here we report the realization of room-temperature skyrmion-like polar nanodomains in lead titanate/strontium titanate bilayers transferred onto silicon. Moreover, an external electric field can reversibly switch these nanodomains into the other type of polar texture, which substantially modifies their resistive behaviours. The polar-configuration-modulated resistance is ascribed to the distinct band bending and charge carrier distribution in the core of the two types of polar texture. The integration of high-density (more than 200 gigabits per square inch) switchable skyrmion-like polar nanodomains on silicon may enable non-volatile memory applications using topological polar structures in oxides.
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12
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Ramesh R. Materials for a Sustainable Microelectronics Future: Electric Field Control of Magnetism with Multiferroics. J Indian Inst Sci 2022; 102:489-511. [PMID: 35035127 PMCID: PMC8749116 DOI: 10.1007/s41745-021-00277-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/23/2021] [Indexed: 11/30/2022]
Abstract
This article is written on behalf of many colleagues, collaborators, and researchers in the field of complex oxides as well as current and former students and postdocs who continue to enable and undertake cutting-edge research in the field of multiferroics, magnetoelectrics, and the pursuit of electric-field control of magnetism. What I present is something that is extremely exciting from both a fundamental science and applications perspective and has the potential to revolutionize our world, particularly from a sustainability perspective. To realize this potential will require numerous new innovations, both in the fundamental science arena as well as translating these scientific discoveries into real applications. Thus, this article will attempt to bridge the gap between fundamental materials physics and the actual manifestations of the physical concepts into real-life applications. I hope this article will help spur more translational research within the broad materials community.
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Affiliation(s)
- R Ramesh
- Department of Physics and Department of Materials Science and Engineering, University of California, Berkeley, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, USA
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13
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Grünebohm A, Marathe M, Khachaturyan R, Schiedung R, Lupascu DC, Shvartsman VV. Interplay of domain structure and phase transitions: theory, experiment and functionality. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:073002. [PMID: 34731841 DOI: 10.1088/1361-648x/ac3607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Domain walls and phase boundaries are fundamental ingredients of ferroelectrics and strongly influence their functional properties. Although both interfaces have been studied for decades, often only a phenomenological macroscopic understanding has been established. The recent developments in experiments and theory allow to address the relevant time and length scales and revisit nucleation, phase propagation and the coupling of domains and phase transitions. This review attempts to specify regularities of domain formation and evolution at ferroelectric transitions and give an overview on unusual polar topological structures that appear as transient states and at the nanoscale. We survey the benefits, validity, and limitations of experimental tools as well as simulation methods to study phase and domain interfaces. We focus on the recent success of these tools in joint scale-bridging studies to solve long lasting puzzles in the field and give an outlook on recent trends in superlattices.
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Affiliation(s)
- Anna Grünebohm
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
| | - Madhura Marathe
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
- Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Ruben Khachaturyan
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
| | - Raphael Schiedung
- Interdisciplinary Centre for Advanced Materials Simulations (ICAMS), Ruhr-University Bochum, 44801 Bochum, Germany
- National Institute for Material Science (NIMS), Tsukuba 305-0047, Japan
| | - Doru C Lupascu
- Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Vladimir V Shvartsman
- Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
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14
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Guan S, Zhang G, Liu C. Enhanced in-plane ferroelectricity, antiferroelectricity, and unconventional 2D emergent fermions in quadruple-layer XSbO 2 (X = Li, Na). NANOSCALE 2021; 13:19172-19180. [PMID: 34781325 DOI: 10.1039/d1nr06051a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Low-dimensional ferroelectricity and Dirac materials with protected band crossings are fascinating research subjects. Based on first-principles calculations, we predict the coexistence of spontaneous in-plane polarization and novel 2D emergent fermions in dynamically stable quadruple-layer (QL) XSbO2 (X = Li, Na). Depending on the different polarization configurations, QL-XSbO2 can exhibit unconventional inner-QL ferroelectricity and antiferroelectricity. Both ground states harbor robust ferroelectricity with enhanced spontaneous polarization of 0.56 nC m-1 and 0.39 nC m-1 for QL-LiSbO2 and QL-NaSbO2, respectively. Interestingly, the QL-LiSbO2 possesses two other metastable ferroelectric (FE) phases. The ground FE phase can be flexibly driven into one of the two metastable FE phases and then into the antiferroelectric (AFE) phase. During this phase transition, several types of 2D fermions emerge, for instance, hourglass hybrid and type-II Weyl loops in the ground FE phase, type-II Weyl fermionsin the metastable FE phase, and type-II Dirac fermions in the AFE phase. These 2D fermions are robust under spin-orbit coupling. Notably, two of these fermions, e.g., an hourglass hybrid or type-II Weyl loop, have not been observed before. Our findings identify QL-XSbO2 as a unique platform for studying 2D ferroelectricity relating to 2D emergent fermions.
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Affiliation(s)
- Shan Guan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
| | - GuangBiao Zhang
- Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
- International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, Henan University, Kaifeng 475004, China
| | - Chang Liu
- Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004, China.
- International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, Henan University, Kaifeng 475004, China
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15
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Abstract
Electric field control of magnetism is an extremely exciting area of research, from both a fundamental science and an applications perspective and has the potential to revolutionize the world of computing. To realize this will require numerous further innovations, both in the fundamental science arena as well as translating these scientific discoveries into real applications. Thus, this article will attempt to bridge the gap between condensed matter physics and the actual manifestations of the physical concepts into applications. We have attempted to paint a broad-stroke picture of the field, from the macroscale all the way down to the fundamentals of spin–orbit coupling that is a key enabler of the physics discussed. We hope it will help spur more translational research within the broad materials physics community. Needless to say, this article is written on behalf of a large number of colleagues, collaborators and researchers in the field of complex oxides as well as current and former students and postdocs who continue to pursue cutting-edge research in this field.
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Affiliation(s)
- Ramamoorthy Ramesh
- Department of Physics, University of California, Berkeley, CA, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA, USA
| | - Sasikanth Manipatruni
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kepler Computing, Portland, OR 97229, USA
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16
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Zhang S, Wang J, Wen S, Jiang M, Xiao H, Ding X, Wang N, Li M, Zu X, Li S, Yam C, Huang B, Qiao L. Approaching Charge Separation Efficiency to Unity without Charge Recombination. PHYSICAL REVIEW LETTERS 2021; 126:176401. [PMID: 33988439 DOI: 10.1103/physrevlett.126.176401] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/30/2020] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
Improving the efficiency of charge separation (CS) and charge transport (CT) is essential for almost all optoelectronic applications, yet its maximization remains a big challenge. Here we propose a conceptual strategy to achieve CS efficiency close to unity and simultaneously avoid charge recombination (CR) during CT in a ferroelectric polar-discontinuity (PD) superlattice structure, as demonstrated in (BaTiO_{3})_{m}/(BiFeO_{3})_{n}, which is fundamentally different from the existing mechanisms. The competition of interfacial dipole and ferroelectric PD induces opposite band bending in BiFeO_{3} and BaTiO_{3} sublattices. Consequently, the photoexcited electrons (e) and holes (h) in individual sublattices move forward to the opposite interfaces forming electrically isolated e and h channels, leading to a CS efficiency close to unity. Importantly, the spatial isolation of conduction channels in (BaTiO_{3})_{m}/(BiFeO_{3})_{n} enable suppression of CR during CT, thus realizing a unique band diagram for spatially orthogonal CS and CT. Remarkably, (BaTiO_{3})_{m}/(BiFeO_{3})_{n} can maintain a high photocurrent and large band gap simultaneously. Our results provide a fascinating illumination for designing artificial heterostructures toward ideal CS and CT in optoelectronic applications.
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Affiliation(s)
- Sa Zhang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Jianfeng Wang
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Shizheng Wen
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Ming Jiang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Haiyan Xiao
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Xiang Ding
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Ning Wang
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Menglu Li
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Xiaotao Zu
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Sean Li
- School of Materials, University of New South Wales, Sydney 2052, New South Wales Australia
| | - ChiYung Yam
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Bing Huang
- Beijing Computational Science Research Center, Beijing, 100193, China
- Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Liang Qiao
- School of Physics, University of Electronic Science and Technology of China, Chengdu 610054, China
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17
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Sati A, Pokhriyal P, Kumar A, Anwar S, Sagdeo A, Lalla NP, Sagdeo PR. Origin of ferroelectricity in cubic phase of Hf substituted BaTiO 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:165403. [PMID: 33752190 DOI: 10.1088/1361-648x/abf0bf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
The origin of ferroelectricity in the cubic phase of BaTi1-xHfxO3has been investigated. The presence of well-defined ferroelectric polarization versus electric field (PE) hysteresis loop in the samples with global cubic symmetry suggests the presence of 'local polar regions', induced possibly due to the huge difference in the electronegativity and also difference in the ionic radii of Hf+4and Ti+4ions, which may lead to local structural disorder. The presence of polar regions is also supported through the appearance of A1(TO) polar mode in Raman spectra which in principle should be absent in the samples with cubic symmetry. The results are discussed in terms of disorder-induced local dipoles due to the electronegativity difference between Hf and Ti ions.
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Affiliation(s)
- Aanchal Sati
- Material Research Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Indore-453552, India
| | - Preeti Pokhriyal
- Synchrotron Utilization Section, Raja Ramanna Center for Advanced Technology, Indore 452013, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - Anil Kumar
- Material Research Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Indore-453552, India
| | - Shahid Anwar
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar-751-013, India
| | - Archna Sagdeo
- Synchrotron Utilization Section, Raja Ramanna Center for Advanced Technology, Indore 452013, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| | - N P Lalla
- UGC-DAE Consortium for scientific research, University campus, Khandwa road, Indore-452001, India
| | - P R Sagdeo
- Material Research Laboratory, Discipline of Physics, Indian Institute of Technology Indore, Indore-453552, India
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18
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Okenyi MTO, Ratcliff LE, Walsh A. Multi-phonon proton transfer pathway in a molecular organic ferroelectric crystal. Phys Chem Chem Phys 2021; 23:2885-2890. [PMID: 33475125 DOI: 10.1039/d0cp04236f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While the majority of ferroelectrics research has been focused on inorganic ceramics, molecular ferroelectrics can also combine large spontaneous polarization with high Curie temperatures. However, the microscopic mechanism of their ferroelectric switching is not fully understood. We explore proton tautomerism in the prototypical case of croconic acid, C5O5H2. In order to determine how efficiently ferroelectricity in croconic acid is described in terms of its Γ-point phonon modes, the minimum energy path between its structural ground states is approximated by projection onto reduced basis sets formed from subsets of these modes. The potential energy curve along the minimum energy path was found to be sensitive to the order of proton transfer, which requires a large subset (⪆8) of the modes to be approximated accurately. Our findings suggest rules for the construction of effective Hamiltonians to describe proton transfer ferroelectrics.
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Affiliation(s)
| | - Laura E Ratcliff
- Department of Materials, Imperial College London, London SW7 2AZ, UK.
| | - Aron Walsh
- Department of Materials, Imperial College London, London SW7 2AZ, UK. and Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Korea
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19
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Bennett D, Muñoz Basagoiti M, Artacho E. Electrostatics and domains in ferroelectric superlattices. ROYAL SOCIETY OPEN SCIENCE 2020; 7:201270. [PMID: 33391805 PMCID: PMC7735331 DOI: 10.1098/rsos.201270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/14/2020] [Indexed: 06/10/2023]
Abstract
The electrostatics arising in ferroelectric/dielectric two-dimensional heterostructures and superlattices is revisited within a Kittel model in order to define and complete a clear paradigmatic reference for domain formation. The screening of the depolarizing field in isolated ferroelectric or polar thin films via the formation of 180° domains is well understood, where the width of the domains w grows as the square-root of the film thickness d, following Kittel's Law for thick enough films (w ≪ d). For thinner films, a minimum is reached for w before diverging to a monodomain. Although this behaviour is known to be qualitatively unaltered when the dielectric environment of the film is modified, we consider the quantitative changes in that behaviour induced on the ferroelectric film by different dielectric settings: as deposited on a dielectric substrate, sandwiched between dielectrics, and in a superlattice of alternating ferroelectric/dielectric films. The model assumes infinitely thin domain walls, and therefore is not expected to be reliable for film thickness in the nanometre scale. The polarization field P(r) does vary in space, deviating from ±P S , following the depolarizing field in linear response, but the model does not include a polarization-gradient term as would appear in a Ginzburg-Landau free energy. The model is, however, worth characterizing, both as paradigmatic reference, and as applicable to not-so-thin films. The correct renormalization of parameters is obtained for the thick-film square-root behaviour in the mentioned settings, and the sub-Kittel regime is fully characterized. New results are presented alongside well-known ones for a comprehensive description. Among the former, a natural separation between strong and weak ferroelectric coupling in superlattices is found, which depends exclusively on the dielectric anisotropy of the ferroelectric layer.
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Affiliation(s)
- Daniel Bennett
- Theory of Condensed Matter, Cavendish Laboratory, Department of Physics, J J Thomson Avenue, Cambridge CB3 0HE, UK
| | - Maitane Muñoz Basagoiti
- Faculty of Science and Technology, University of the Basque Country, Barrio Sarriena 48940 Leioa, Spain
- Gulliver Lab UMR 7083, ESPCI PSL Research University, 75005 Paris, France
- CIC Nanogune and DIPC, Tolosa Hiribidea 76, 20018 San Sebastian, Spain
| | - Emilio Artacho
- Theory of Condensed Matter, Cavendish Laboratory, Department of Physics, J J Thomson Avenue, Cambridge CB3 0HE, UK
- CIC Nanogune and DIPC, Tolosa Hiribidea 76, 20018 San Sebastian, Spain
- Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
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20
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Xie N, Zhang J, Raza S, Zhang N, Chen X, Wang D. Generation of low-symmetry perovskite structures for ab initiocomputation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:315901. [PMID: 32163934 DOI: 10.1088/1361-648x/ab7f6a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/12/2020] [Indexed: 06/10/2023]
Abstract
Ion displacements are the fundamental cause of ferroelectricity in perovskites. By properly shifting ions,ab initiocomputations have been extensively used to investigate the properties of perovskites in various structural phases. In addition to the relatively simple ion displacements, perovskites have another type of structural distortion known as antiferrodistortion or oxygen octahedron tilting. The interplay between these two types of distortions have generated abundant structural phases that can be tedious to prepare forab initiocomputation, especially for large supercells. Here, we design and implement a computer program to facilitate the generation of distorted perovskite structures, which can be readily used forab initiocomputation to gain further insight into the perovskite of a given structural phase.
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Affiliation(s)
- N Xie
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - J Zhang
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - S Raza
- School of Energy and Environment, City University of Hong Kong, Kowloon 999077, Hong Kong Special Administrative Region, People's Republic of China
| | - N Zhang
- Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education & International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - X Chen
- Department of Applied Physics, Aalto University, Espoo 00076, Finland
- BroadBit Batteries Oy, Espoo 02150, Finland
| | - D Wang
- School of Microelectronics & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
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21
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Varignon J, Bristowe NC, Bousquet E, Ghosez P. Magneto-electric multiferroics: designing new materials from first-principles calculations. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2019-0069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In parallel with the revival of interest for magneto-electric multiferroic materials in the beginning of the century, first-principles simulations have grown incredibly in efficiency during the last two decades. Density functional theory calculations, in particular, have so become a must-have tool for physicists and chemists in the multiferroic community. While these calculations were originally used to support and explain experimental behaviour, their interest has progressively moved to the design of novel magneto-electric multiferroic materials. In this article, we mainly focus on oxide perovskites, an important class of multifunctional material, and review some significant advances to which contributed first-principles calculations. We also briefly introduce the various theoretical developments that were at the core of all these advances.
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22
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Abstract
In recent years, finite strain Landau theory has been gradually developed as both a conceptual as well as a quantitative framework to study high pressure phase transitions of the group-subgroup type. In the current paper, we introduce a new version of this approach which is based on symmetry-adapted finite strains. This results in a substantial simplification of the original formulation. Moreover, it allows for replacing the clumsy use of truncated Taylor expansions by a convenient functional parametrization. Both the weaknesses of the traditional Landau approach based on infinitesimal strains as well as the major improvements made possible by our new parametrization are illustrated in great detail in an application to the ambient temperature high pressure transition of the perovskite KMnF 3 .
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23
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Ozaki H, Tada K, Kiyobayashi T. Monte-Carlo simulation combined with density functional theory to investigate the equilibrium thermodynamics of electrode materials: lithium titanates as model compounds. Phys Chem Chem Phys 2019; 21:15551-15559. [PMID: 31264669 DOI: 10.1039/c9cp02107h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By using lithium titanate (LTO) as a model electrode material, the present study proposes a method to describe its equilibrium thermodynamics based on the Monte-Carlo simulation (MC), for which the energetic parameters are determined by the density functional theory (DFT). The electrochemical potential profile is simulated by a simple topological model which consists only of three parameters representing the Li site energies; namely, the potential energy of the 8a site (ε8a), the difference in the site energy between the 8a and 16c sites (Δε) and the repulsion between two Li atoms situated at the adjacent 8a and 16c sites (J). Parameter physics by the MC revealed that the term Δε plays a decisive role, with a collateral effect from J, for characterizing the shape of the potential profile whereas the term ε8a determines its position along the electrochemical potential. For instance, if Δε exceeds the thermal energy at the temperature under consideration, i.e., if Δε > 3kT, the first-order phase transition takes place during which two phases coexist, resulting in a plateau region in the potential profile. On the other hand, if Δε < 3kT, the lithiation of LTO is viewed as a phenomenon above the critical point, above which the material is in a homogeneous uniphasic state. A multiple regression analysis of a set of the total energy calculated by DFT allows us to determine these energetic terms. The MC simulation with the determined parameters well reproduces the shape and position of the experimental potential profile of LTO. Since the determined value, Δε/eV ∼ 0.4, far exceeds the thermal energy at ambient temperature, the potential plateau of LTO is explained by the first-order phase transition as long as the equilibrium state is concerned.
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Affiliation(s)
- Hiroyuki Ozaki
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Kohei Tada
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Tetsu Kiyobayashi
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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24
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Zhang J, Hou X, Wang J. Direct and indirect methods based on effective Hamilton for electrocaloric effect of BaTiO 3 nanoparticle. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:255402. [PMID: 30893666 DOI: 10.1088/1361-648x/ab119b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Low dimensional ferroelectric materials, including nano thin films, nanowires and nanoparticules, exhibit excellent electrocaloric effect (ECE) and have potential application in solid-state cooling devices. Predicting the ECE property of nanoscale ferroelectrics is of scientific significance and practice importance. Here, the direct and indirect methods based on effective Hamilton are employed to study the ECE in BaTiO3 nanoparticle under different electric fields and temperatures. In indirect method, the Monte Carlo simulation is used to obtain the polarization changes with temperature under different electric fields. The ECE is calculated indirectly based on the Maxwell relation. In direct method, the demon energy is introduced into the system in order to obtain the ECE directly. The results shows that the difference between the peak values of direct method and indirect method is less than 5%, which means both direct method and indirect method can be used to simulate the ECE of ferroelectric nanoparticle.
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Affiliation(s)
- Jingtong Zhang
- Department of Engineering Mechanics, School of Aeronautics and Astronautics, Zhejiang University, 38 Zheda Road, Hangzhou 310027, People's Republic of China
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25
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Sayedaghaee SO, Xu B, Prosandeev S, Paillard C, Bellaiche L. Novel Dynamical Magnetoelectric Effects in Multiferroic BiFeO_{3}. PHYSICAL REVIEW LETTERS 2019; 122:097601. [PMID: 30932533 DOI: 10.1103/physrevlett.122.097601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/19/2019] [Indexed: 06/09/2023]
Abstract
An atomistic effective Hamiltonian scheme is employed within molecular dynamics simulations to investigate how the electrical polarization and magnetization of the multiferroic BiFeO_{3} respond to time-dependent ac magnetic fields of various frequencies, as well as to reveal the frequency dependency of the dynamical (quadratic) magnetoelectric coefficient. We found the occurrence of vibrations having phonon frequencies in both the time dependency of the electrical polarization and magnetization (for any applied ac frequency), therefore making such vibrations of electromagnonic nature, when the homogeneous strain of the system is frozen (case 1). Moreover, the quadratic magnetoelectric coupling constant is monotonic and almost dispersionless in the sub-THz range in this case 1. In contrast, when the homogeneous strain can fully relax (case 2), two additional low-frequency and strain-mediated oscillations emerge in the time-dependent behavior of the polarization and magnetization, which result in resonances in the quadratic magnetoelectric coefficient. Such additional oscillations consist of a mixing between acoustic phonons, optical phonons, and magnons, and reflect the existence of a new quasiparticle that can be coined an "electroacoustic magnon." This latter finding can prompt experimentalists to shape their samples to take advantage of, and tune, the magnetostrictive-induced mechanical resonance frequency, in order to achieve large dynamical magnetoelectric couplings.
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Affiliation(s)
- S Omid Sayedaghaee
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Microelectronics-Photonics Program, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Bin Xu
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- School of Physical Science and Technology, Soochow University, Suzhou, Jiangsu 215006, China
| | - Sergey Prosandeev
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute of Physics and Physics Department of Southern Federal University, Rostov-na-Donu 344090, Russia
| | - Charles Paillard
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Laboratoire Structures, Propriétés et Modélisation des Solides, CentraleSupélec, CNRS UMR 8580, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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26
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Spaldin NA, Ramesh R. Advances in magnetoelectric multiferroics. NATURE MATERIALS 2019; 18:203-212. [PMID: 30783227 DOI: 10.1038/s41563-018-0275-2] [Citation(s) in RCA: 301] [Impact Index Per Article: 60.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 12/17/2018] [Indexed: 05/05/2023]
Abstract
The manipulation of magnetic properties by an electric field in magnetoelectric multiferroic materials has driven significant research activity, with the goal of realizing their transformative technological potential. Here, we review progress in the fundamental understanding and design of new multiferroic materials, advances in characterization and modelling tools to describe them, and the exploration of devices and applications. Focusing on the translation of the many scientific breakthroughs into technological innovations, we identify the key open questions in the field where targeted research activities could have maximum impact in transitioning scientific discoveries into real applications.
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Affiliation(s)
- N A Spaldin
- Materials Theory, ETH Zurich, Zürich, Switzerland.
| | - R Ramesh
- Department of Materials Science and Engineering, UC Berkeley, Berkeley, CA, USA
- Department of Physics, UC Berkeley, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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27
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Pereira Gonçalves MA, Escorihuela-Sayalero C, Garca-Fernández P, Junquera J, Íñiguez J. Theoretical guidelines to create and tune electric skyrmion bubbles. SCIENCE ADVANCES 2019; 5:eaau7023. [PMID: 30793029 PMCID: PMC6377273 DOI: 10.1126/sciadv.aau7023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 12/28/2018] [Indexed: 05/21/2023]
Abstract
Researchers have long wondered whether ferroelectrics may present topological textures akin to magnetic skyrmions and chiral bubbles, the results being modest thus far. An electric equivalent of a typical magnetic skyrmion would rely on a counterpart of the Dzyaloshinskii-Moriya interaction and seems all but impossible; further, the exotic ferroelectric orders reported to date rely on specific composites and superlattices, limiting their generality and properties. Here, we propose an original approach to write topological textures in simple ferroelectrics in a customary manner. Our second-principles simulations of columnar nanodomains, in prototype material PbTiO3, show we can harness the Bloch-type structure of the domain wall to create objects with the usual skyrmion-defining features as well as unusual ones-including isotopological and topological transitions driven by external fields and temperature-and potentially very small sizes. Our results suggest countless possibilities for creating and manipulating such electric textures, effectively inaugurating the field of topological ferroelectrics.
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Affiliation(s)
- M. A. Pereira Gonçalves
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux 5, L-4362 Esch/Alzette, Luxembourg
| | - Carlos Escorihuela-Sayalero
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux 5, L-4362 Esch/Alzette, Luxembourg
| | - Pablo Garca-Fernández
- Departamento de Ciencias de la Tierra y Fsica de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, Avenida de los Castros s/n, 39005 Santander, Spain
| | - Javier Junquera
- Departamento de Ciencias de la Tierra y Fsica de la Materia Condensada, Universidad de Cantabria, Cantabria Campus Internacional, Avenida de los Castros s/n, 39005 Santander, Spain
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), Avenue des Hauts-Fourneaux 5, L-4362 Esch/Alzette, Luxembourg
- Physics and Materials Science Research Unit, University of Luxembourg, 41 Rue du Brill, L-4422 Belvaux, Luxembourg
- Corresponding author.
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28
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Akbarian D, Yilmaz DE, Cao Y, Ganesh P, Dabo I, Munro J, Van Ginhoven R, van Duin ACT. Understanding the influence of defects and surface chemistry on ferroelectric switching: a ReaxFF investigation of BaTiO 3. Phys Chem Chem Phys 2019; 21:18240-18249. [PMID: 31393478 DOI: 10.1039/c9cp02955a] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ferroelectric materials such as barium titanate (BaTiO3) have a wide range of applications in nano scale electronic devices due to their outstanding properties. In this study, we developed an easily extendable atomistic ReaxFF reactive force field for BaTiO3 that can capture both its field- and temperature-induced ferroelectric hysteresis and corresponding changes due to surface chemistry and bulk defects. Using our force field, we were able to reproduce and explain a number of experimental observations: (1) the existence of a critical thickness of 4.8 nm below which ferroelectricity vanishes in BaTiO3; (2) migration and clustering of oxygen vacancies (OVs) in BaTiO3 and a reduction in the polarization and the Curie temperature due to the OVs; (3) domain wall interaction with the surface chemistry to influence the ferroelectric switching and polarization magnitude. This new computational tool opens up a wide range of possibilities for making predictions for realistic ferroelectric interfaces in energy-conversion, electronic and neuromorphic systems.
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Affiliation(s)
- Dooman Akbarian
- Department of Mechanical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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29
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Yoshida S, Akamatsu H, Tsuji R, Hernandez O, Padmanabhan H, Sen Gupta A, Gibbs AS, Mibu K, Murai S, Rondinelli JM, Gopalan V, Tanaka K, Fujita K. Hybrid Improper Ferroelectricity in (Sr,Ca)3Sn2O7 and Beyond: Universal Relationship between Ferroelectric Transition Temperature and Tolerance Factor in n = 2 Ruddlesden–Popper Phases. J Am Chem Soc 2018; 140:15690-15700. [PMID: 30347981 DOI: 10.1021/jacs.8b07998] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Suguru Yoshida
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | | | - Ryosuke Tsuji
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - Olivier Hernandez
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, F-35000 Rennes, France
| | | | | | - Alexandra S. Gibbs
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, U.K
| | - Ko Mibu
- Department of Physical Science and Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan
| | - Shunsuke Murai
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - James M. Rondinelli
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | | | - Katsuhisa Tanaka
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
| | - Koji Fujita
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Nishikyo-ku, Kyoto 615-8510, Japan
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30
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Ye QJ, Liu ZY, Feng Y, Gao P, Li XZ. Ferroelectric Problem beyond the Conventional Scaling Law. PHYSICAL REVIEW LETTERS 2018; 121:135702. [PMID: 30312051 DOI: 10.1103/physrevlett.121.135702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Ferroelectric (FE) size effects against the scaling law were reported recently in ultrathin group-IV monochalcogenides, and extrinsic effects (e.g., defects and lattice strains) were often resorted to. Via first-principles based finite-temperature (T) simulations, we reveal that these abnormalities are intrinsic to their unusual symmetry breaking from bulk to thin film. Changes of the electronic structures result in different order parameters characterizing the FE phase transition in bulk and in thin films, and invalidation of the scaling law. Beyond the scaling law T_{c} limit, this mechanism can help predict materials that are promising for room-T ultrathin FE devices of broad interest.
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Affiliation(s)
- Qi-Jun Ye
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, and School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Zhi-Yuan Liu
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, and School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yexin Feng
- School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Peng Gao
- International Center for Quantum Materials, and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, People's Republic of China
| | - Xin-Zheng Li
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, and School of Physics, Peking University, Beijing 100871, People's Republic of China
- Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, People's Republic of China
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31
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Monserrat B, Drummond ND, Dalladay-Simpson P, Howie RT, López Ríos P, Gregoryanz E, Pickard CJ, Needs RJ. Structure and Metallicity of Phase V of Hydrogen. PHYSICAL REVIEW LETTERS 2018; 120:255701. [PMID: 29979086 DOI: 10.1103/physrevlett.120.255701] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 05/17/2018] [Indexed: 06/08/2023]
Abstract
A new phase V of hydrogen was recently claimed in experiments above 325 GPa and 300 K. Because of the extremely small sample size at such record pressures the measurements were limited to Raman spectroscopy. The experimental data on increase of pressure show decreasing Raman activity and darkening of the sample, which suggests band gap closure and impending molecular dissociation, but no definite conclusions could be reached. Furthermore, the available data are insufficient to determine the structure of phase V, which remains unknown. Introducing saddle-point ab initio random structure searching, we find several new structural candidates of hydrogen which could describe the observed properties of phase V. We investigate hydrogen metallization in the proposed candidate structures, and demonstrate that smaller band gaps are associated with longer bond lengths. We conclude that phase V is a stepping stone towards metallization.
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Affiliation(s)
- Bartomeu Monserrat
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA
- TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Neil D Drummond
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Philip Dalladay-Simpson
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
| | - Ross T Howie
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
| | - Pablo López Ríos
- TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Max-Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Eugene Gregoryanz
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
- Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Chris J Pickard
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
- Advanced Institute for Materials Research, Tohoku University 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Richard J Needs
- TCM Group, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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Bin-Omran S. The influence of mechanical and electrical boundary conditions on electrocaloric response in (Ba0.50Sr0.50)TiO3 thin films. MATERIALS RESEARCH BULLETIN 2017; 95:334-338. [DOI: 10.1016/j.materresbull.2017.07.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Cazorla C, Diéguez O, Íñiguez J. Multiple structural transitions driven by spin-phonon couplings in a perovskite oxide. SCIENCE ADVANCES 2017; 3:e1700288. [PMID: 28695196 PMCID: PMC5493420 DOI: 10.1126/sciadv.1700288] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/12/2017] [Indexed: 06/07/2023]
Abstract
Spin-phonon interactions are central to many interesting phenomena, ranging from superconductivity to magnetoelectric effects. However, they are believed to have a negligible influence on the structural behavior of most materials. For example, magnetic perovskite oxides often undergo structural transitions accompanied by magnetic signatures whose minuteness suggests that the underlying spin-phonon couplings are largely irrelevant. We present an exception to this rule, showing that novel effects can occur as a consequence. Our first-principles calculations reveal that spin-phonon interactions are essential to reproduce the experimental observations on the phase diagram of magnetoelectric multiferroic BiCoO3. Moreover, we predict that, under compression, these couplings lead to an unprecedented temperature-driven double-reentrant sequence of ferroelectric transitions. We propose how to modify BiCoO3 via chemical doping to reproduce such marked effects under ambient conditions, thereby yielding useful multifunctionality.
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Affiliation(s)
- Claudio Cazorla
- School of Materials Science and Engineering and Integrated Materials Design Centre, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Oswaldo Diéguez
- Department of Materials Science and Engineering, Faculty of Engineering, and The Raymond and Beverly Sackler Center for Computational Molecular and Materials Science, Tel Aviv University, IL-69978 Tel Aviv, Israel
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology, 5 avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg
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34
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Bin-Omran S. Thickness dependence of electrocaloric response in ferroelectric thin films. MATERIALS LETTERS 2017; 196:351-353. [DOI: 10.1016/j.matlet.2017.03.086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Xu B, Íñiguez J, Bellaiche L. Designing lead-free antiferroelectrics for energy storage. Nat Commun 2017; 8:15682. [PMID: 28555655 PMCID: PMC5499206 DOI: 10.1038/ncomms15682] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/18/2017] [Indexed: 12/24/2022] Open
Abstract
Dielectric capacitors, although presenting faster charging/discharging rates and better stability compared with supercapacitors or batteries, are limited in applications due to their low energy density. Antiferroelectric (AFE) compounds, however, show great promise due to their atypical polarization-versus-electric field curves. Here we report our first-principles-based theoretical predictions that Bi1-xRxFeO3 systems (R being a lanthanide, Nd in this work) can potentially allow high energy densities (100-150 J cm-3) and efficiencies (80-88%) for electric fields that may be within the range of feasibility upon experimental advances (2-3 MV cm-1). In addition, a simple model is derived to describe the energy density and efficiency of a general AFE material, providing a framework to assess the effect on the storage properties of variations in doping, electric field magnitude and direction, epitaxial strain, temperature and so on, which can facilitate future search of AFE materials for energy storage.
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Affiliation(s)
- Bin Xu
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Jorge Íñiguez
- Materials Research and Technology Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, Esch/Alzette L-4362, Luxembourg
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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36
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Deretzis I, La Magna A. Exploring the orthorhombic-tetragonal phase transition in CH 3NH 3PbI 3: the role of atom kinetics. NANOSCALE 2017; 9:5896-5903. [PMID: 28436512 DOI: 10.1039/c7nr01818e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Methylammonium lead tri-iodide is a polymorphic material with two temperature-induced phase transitions at 165 K and 327 K, accompanied by an orthorhombic-to-tetragonal and a tetragonal-to-cubic lattice modification. Understanding the origins of these transitions as well as their implications on the crystal structure of the material is fundamental for its technological optimization. Here, we use the density functional theory along with ab initio molecular dynamics to study the low-temperature phase transition of CH3NH3PbI3. Considering two kinetically robust models for the orthorhombic and the tetragonal phase, we show that the vibrational features of the material can be strongly affected by the orientations of the methylammonium ions. We argue that the orthorhombic-tetragonal transition is characterized by a partial rearrangement of the organic cations that locally relaxes the stress induced by the thermal movement of atoms. We finally propose a macroscopic model for the tetragonal phase that consists of rotated noncentrosymmetric domains, where the methylammonium ions are quasi-two-dimensionally confined around the a-b crystallographic plane.
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Affiliation(s)
- Ioannis Deretzis
- Institute for Microelectronics and Microsystems (CNR-IMM), Z.I. VIII strada 5, 95121 Catania, Italy.
| | - Antonino La Magna
- Institute for Microelectronics and Microsystems (CNR-IMM), Z.I. VIII strada 5, 95121 Catania, Italy.
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Yuk SF, Pitike KC, Nakhmanson SM, Eisenbach M, Li YW, Cooper VR. Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects. Sci Rep 2017; 7:43482. [PMID: 28256544 PMCID: PMC5335310 DOI: 10.1038/srep43482] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/16/2017] [Indexed: 11/23/2022] Open
Abstract
Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.
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Affiliation(s)
- Simuck F Yuk
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA
| | - Krishna Chaitanya Pitike
- Department of Materials Science & Engineering, and Institute of Materials Science, University of Connecticut, Storrs, 06269, Connecticut, USA
| | - Serge M Nakhmanson
- Department of Materials Science & Engineering, and Institute of Materials Science, University of Connecticut, Storrs, 06269, Connecticut, USA
| | - Markus Eisenbach
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA
| | - Ying Wai Li
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA
| | - Valentino R Cooper
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA.
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38
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Bin-Omran S. Influence of strain on an epitaxial ferroelectric (Ba 0.50 Sr 0.50 )TiO 3 nanodot under different electrical boundary conditions. PHYSICA E: LOW-DIMENSIONAL SYSTEMS AND NANOSTRUCTURES 2017; 86:58-63. [DOI: 10.1016/j.physe.2016.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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39
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Improper electric polarization in simple perovskite oxides with two magnetic sublattices. Nat Commun 2017; 8:14025. [PMID: 28106057 PMCID: PMC5263889 DOI: 10.1038/ncomms14025] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 11/21/2016] [Indexed: 11/08/2022] Open
Abstract
ABO3 perovskite oxides with magnetic A and B cations offer a unique playground to explore interactions involving two spin sublattices and the emergent effects they may drive. Of particular interest is the possibility of having magnetically driven improper ferroelectricity, as in the much studied families of rare-earth orthoferrites and orthochromites; yet, the mechanisms behind such effects remain to be understood in detail. Here we show that the strongest polar order corresponds to collinear spin configurations and is driven by non-relativistic exchange-strictive mechanisms. Our first-principles simulations reveal the dominant magnetostructural couplings underlying the observed ferroelectricity, including a striking magnetically driven piezoelectric effect. Further, we derive phenomenological and atomistic theories that describe such couplings in a generic perovskite lattice. This allows us to predict how the observed effects can be enhanced, and even how similar ones can be obtained in other perovskite families. Magnetically-driven ferroelectricity holds the key for novel multiferroic effects in perovskite oxides, but it remains poorly understood. Here, Zhao et al. determine the dominant magnetostructural couplings that yield improper ferroelectricity in a generic perovskite with two spin sublattices.
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Jiang Z, Nahas Y, Xu B, Prosandeev S, Wang D, Bellaiche L. Special quasirandom structures for perovskite solid solutions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:475901. [PMID: 27661191 DOI: 10.1088/0953-8984/28/47/475901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Special quasirandom structures (SQS) are presently generated for disordered (A'1-x [Formula: see text] x )BX3 and A(B'1-x [Formula: see text] x )X3 perovskite solid solutions, with x = 1/2 as well as 1/3 and 2/3. These SQS configurations are obtained by imposing that the so-called Cowley parameters are as close to zero as possible for the three nearest neighboring shells. Moreover, these SQS configurations are slightly larger in size than those available in the literature for x = 1/2, mostly because of the current capabilities of atomistic techniques. They are used here within effective Hamiltonian schemes to predict various properties, which are then compared to those associated with large random supercells, in a variety of compounds, namely (Ba1-x Sr x )TiO3, Pb(Zr1-x Ti x )O3, Pb(Sc0.5Nb0.5)O3, Ba(Zr1-x Ti x )O3, Pb(Mg1/3Nb2/3)O3 and (Bi1-x Nd x )FeO3. It is found that these SQS configurations can reproduce many properties of large random supercells of most of these disordered perovskite alloys, below some finite material-dependent temperature. Examples of these properties are electrical polarization, anti-phase and in-phase octahedral tiltings, antipolar motions, antiferromagnetism, strain, piezoelectric coefficients, dielectric response, specific heat and even the formation of polar nanoregions (PNRs) in some relaxors. Some limitations of these SQS configurations are also pointed out and explained.
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Affiliation(s)
- Zhijun Jiang
- School of Electronic and Information Engineering & State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China. Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, AR 72701, USA
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41
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Fei R, Kang W, Yang L. Ferroelectricity and Phase Transitions in Monolayer Group-IV Monochalcogenides. PHYSICAL REVIEW LETTERS 2016; 117:097601. [PMID: 27610884 DOI: 10.1103/physrevlett.117.097601] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Indexed: 05/25/2023]
Abstract
Ferroelectricity usually fades away as materials are thinned down below a critical value. We reveal that the unique ionic-potential anharmonicity can induce spontaneous in-plane electrical polarization and ferroelectricity in monolayer group-IV monochalcogenides MX (M=Ge, Sn; X=S, Se). An effective Hamiltonian has been successfully extracted from the parametrized energy space, making it possible to study the ferroelectric phase transitions in a single-atom layer. The ferroelectricity in these materials is found to be robust and the corresponding Curie temperatures are higher than room temperature, making them promising for realizing ultrathin ferroelectric devices of broad interest. We further provide the phase diagram and predict other potentially two-dimensional ferroelectric materials.
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Affiliation(s)
- Ruixiang Fei
- Department of Physics and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Wei Kang
- HEDPS, Center for Applied Physics and Technology, and College of Engineering, Peking University, Beijing 100871, China
| | - Li Yang
- Department of Physics and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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42
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Adams DJ, Passerone D. Insight into structural phase transitions from the decoupled anharmonic mode approximation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:305401. [PMID: 27269514 DOI: 10.1088/0953-8984/28/30/305401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We develop a formalism (decoupled anharmonic mode approximation, DAMA) that allows calculation of the vibrational free energy using density functional theory even for materials which exhibit negative curvature of the potential energy surface with respect to atomic displacements. We investigate vibrational modes beyond the harmonic approximation and approximate the potential energy surface with the superposition of the accurate potential along each normal mode. We show that the free energy can stabilize crystal structures at finite temperatures which appear dynamically unstable at T = 0. The DAMA formalism is computationally fast because it avoids statistical sampling through molecular dynamics calculations, and is in principle completely ab initio. It is free of statistical uncertainties and independent of model parameters, but can give insight into the mechanism of a structural phase transition. We apply the formalism to the perovskite cryolite, and investigate the temperature-driven phase transition from the P21/n to the Immm space group. We calculate a phase transition temperature between 710 and 950 K, in fair agreement with the experimental value of 885 K. This can be related to the underestimation of the interaction of the vibrational states. We also calculate the main axes of the thermal ellipsoid and can explain the experimentally observed increase of its volume for the fluorine by 200-300% throughout the phase transition. Our calculations suggest the appearance of tunneling states in the high temperature phase. The convergence of the vibrational DOS and of the critical temperature with respect of reciprocal space sampling is investigated using the polarizable-ion model.
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Affiliation(s)
- Donat J Adams
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
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43
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Bin-Omran S. Phase-transition character in (Ba0.50,Sr0.50)TiO3 nanodots from first principles. JOURNAL OF ALLOYS AND COMPOUNDS 2016; 674:82-88. [DOI: 10.1016/j.jallcom.2016.03.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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44
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Geneste G, Bellaiche L, Kiat JM. Simulating the Radio-Frequency Dielectric Response of Relaxor Ferroelectrics: Combination of Coarse-Grained Hamiltonians and Kinetic Monte Carlo Simulations. PHYSICAL REVIEW LETTERS 2016; 116:247601. [PMID: 27367408 DOI: 10.1103/physrevlett.116.247601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Indexed: 06/06/2023]
Abstract
The radio-frequency dielectric response of the lead-free Ba(Zr_{0.5}Ti_{0.5})O_{3} relaxor ferroelectric is simulated using a coarse-grained Hamiltonian. This concept, taken from real-space renormalization group theories, allows us to depict the collective behavior of correlated local modes gathered in blocks. Free-energy barriers for their thermally activated collective hopping are deduced from this ab initio-based approach, and used as input data for kinetic Monte Carlo simulations. The resulting numerical scheme allows us to simulate the dielectric response for external field frequencies ranging from kHz up to a few tens of MHz for the first time and to demonstrate, e.g., that local (electric or elastic) random fields lead to the dielectric relaxation in the radio-frequency range that has been observed in relaxors.
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Affiliation(s)
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Jean-Michel Kiat
- Laboratoire Structures, Propriétés et Modélisation des Solides, Université Paris Saclay, CentraleSupélec, CNRS (UMR 8580), Grande Voie des Vignes, 92295 Châtenay-Malabry, France
- LLB, CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette, France
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45
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Nahas Y, Prokhorenko S, Kornev I, Bellaiche L. Topological Point Defects in Relaxor Ferroelectrics. PHYSICAL REVIEW LETTERS 2016; 116:127601. [PMID: 27058101 DOI: 10.1103/physrevlett.116.127601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Indexed: 06/05/2023]
Abstract
First-principles-based effective Hamiltonian simulations are used to reveal the hidden connection between topological defects (hedgehogs and antihedgehogs) and relaxor behavior. Such defects are discovered to predominantly lie at the border of polar nanoregions in both Ba(Zr_{0.5}Ti_{0.5})O_{3} (BZT) and Pb(Sc_{0.5}Nb_{0.5})O_{3} (PSN) systems, and the temperature dependency of their density allows us to distinguish between noncanonical (PSN) and canonical (BZT) relaxor behaviors (via the presence or absence of a crossing of a percolation threshold). This density also possesses an inflection point at precisely the temperature for which the dielectric response peaks. Moreover, hedgehogs and antihedgehogs are found to be mobile excitations, and the dynamical nature of their annihilation is demonstrated (using simple hydrodynamical arguments) to follows laws, such as those of Vogel-Fulcher and Arrhenius, that are characteristic of dipolar relaxation kinetics of relaxor ferroelectrics.
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Affiliation(s)
- Y Nahas
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - S Prokhorenko
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - I Kornev
- Laboratoire Structures, Propriétés et Modélisation des Solides, CNRS-UMR8580, Ecole Centrale Paris, 92290 Châtenay-Malabry, France
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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46
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Kumah DP, Dogan M, Ngai JH, Qiu D, Zhang Z, Su D, Specht ED, Ismail-Beigi S, Ahn CH, Walker FJ. Engineered Unique Elastic Modes at a BaTiO_{3}/(2×1)-Ge(001) Interface. PHYSICAL REVIEW LETTERS 2016; 116:106101. [PMID: 27015492 DOI: 10.1103/physrevlett.116.106101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 06/05/2023]
Abstract
The strong interaction at an interface between a substrate and thin film leads to epitaxy and provides a means of inducing structural changes in the epitaxial film. These induced material phases often exhibit technologically relevant electronic, magnetic, and functional properties. The 2×1 surface of a Ge(001) substrate applies a unique type of epitaxial constraint on thin films of the perovskite oxide BaTiO_{3} where a change in bonding and symmetry at the interface leads to a non-bulk-like crystal structure of the BaTiO_{3}. While the complex crystal structure is predicted using first-principles theory, it is further shown that the details of the structure are a consequence of hidden phases found in the bulk elastic response of the BaTiO_{3} induced by the symmetry of forces exerted by the germanium substrate.
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Affiliation(s)
- D P Kumah
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - M Dogan
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - J H Ngai
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - D Qiu
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - Z Zhang
- Argonne National Laboratory, Advanced Photon Source, Argonne, Illinois 60439, USA
| | - D Su
- Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973, USA
| | - E D Specht
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - S Ismail-Beigi
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - C H Ahn
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
| | - F J Walker
- Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520, USA
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Buhot J, Toulouse C, Gallais Y, Sacuto A, de Sousa R, Wang D, Bellaiche L, Bibes M, Barthélémy A, Forget A, Colson D, Cazayous M, Measson MA. Driving Spin Excitations by Hydrostatic Pressure in BiFeO(3). PHYSICAL REVIEW LETTERS 2015; 115:267204. [PMID: 26765020 DOI: 10.1103/physrevlett.115.267204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Indexed: 06/05/2023]
Abstract
Optical spectroscopy has been combined with computational and theoretical techniques to show how the spin dynamics in the model multiferroic BiFeO(3) responds to the application of hydrostatic pressure and its corresponding series of structural phase transitions from R3c to the Pnma phases. As pressure increases, multiple spin excitations associated with noncollinear cycloidal magnetism collapse into two excitations, which show jump discontinuities at some of the ensuing crystal phase transitions. The effective Hamiltonian approach provides information on the electrical polarization and structural changes of the oxygen octahedra through the successive structural phases. The extracted parameters are then used in a Ginzburg-Landau model to reproduce the evolution with pressure of the spin wave excitations observed at low energy, and we demonstrate that the structural phases and the magnetic anisotropy drive and control the spin excitations.
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Affiliation(s)
- J Buhot
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
| | - C Toulouse
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
| | - Y Gallais
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
| | - A Sacuto
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
| | - R de Sousa
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada, V8W 2Y2
| | - D Wang
- Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education, and International Center for Dielectric Research, Xi'an Jiaotong University, Xi'an 710049, China
| | - L Bellaiche
- Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - M Bibes
- Unité Mixte de Physique CNRS/Thales, 1 avenue Augustin Fresnel, Campus de l'Ecole Polytechnique, F-91767 Palaiseau, France et Université Paris-Sud, 91405 Orsay, France
| | - A Barthélémy
- Unité Mixte de Physique CNRS/Thales, 1 avenue Augustin Fresnel, Campus de l'Ecole Polytechnique, F-91767 Palaiseau, France et Université Paris-Sud, 91405 Orsay, France
| | - A Forget
- Service de Physique de l'Etat Condensé, CEA Saclay, IRAMIS, SPEC (CNRS URA 2464), F-91191 Gif sur Yvette, France
| | - D Colson
- Service de Physique de l'Etat Condensé, CEA Saclay, IRAMIS, SPEC (CNRS URA 2464), F-91191 Gif sur Yvette, France
| | - M Cazayous
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
| | - M-A Measson
- Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot, Bâtiment Condorcet 75205 Paris Cedex 13, France
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48
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Skelton JM, Tiana D, Parker SC, Togo A, Tanaka I, Walsh A. Influence of the exchange-correlation functional on the quasi-harmonic lattice dynamics of II-VI semiconductors. J Chem Phys 2015; 143:064710. [PMID: 26277159 DOI: 10.1063/1.4928058] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We perform a systematic comparison of the finite-temperature structure and properties of four bulk semiconductors (PbS, PbTe, ZnS, and ZnTe) predicted by eight popular exchange-correlation functionals from quasi-harmonic lattice-dynamics calculations. The performance of the functionals in reproducing the temperature dependence of a number of material properties, including lattice parameters, thermal-expansion coefficients, bulk moduli, heat capacities, and phonon frequencies, is evaluated quantitatively against available experimental data. We find that the phenomenological over- and under-binding characteristics of the local-density approximation and the PW91 and Perdew-Burke-Enzerhof (PBE) generalised-gradient approximation (GGA) functionals, respectively, are exaggerated at finite temperature, whereas the PBEsol GGA shows good general performance across all four systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) and revTPSS meta-GGAs provide relatively small improvements over PBE, with the latter being better suited to calculating structural and dynamical properties, but both are considerably more computationally demanding than the simpler GGAs. The dispersion-corrected PBE-D2 and PBE-D3 functionals perform well in describing the lattice dynamics of the zinc chalcogenides, whereas the lead chalcogenides appear to be challenging for these functionals. These findings show that quasi-harmonic calculations with a suitable functional can predict finite-temperature structure and properties with useful accuracy, and that this technique can serve as a means of evaluating the performance of new functionals in the future.
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Affiliation(s)
- Jonathan M Skelton
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Davide Tiana
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Atsushi Togo
- Elements Strategy Initiative for Structural Materials, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Isao Tanaka
- Elements Strategy Initiative for Structural Materials, Kyoto University, Sakyo, Kyoto 606-8501, Japan
| | - Aron Walsh
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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Discovery of stable skyrmionic state in ferroelectric nanocomposites. Nat Commun 2015; 6:8542. [PMID: 26436432 PMCID: PMC4600738 DOI: 10.1038/ncomms9542] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 09/01/2015] [Indexed: 11/08/2022] Open
Abstract
Non-coplanar swirling field textures, or skyrmions, are now widely recognized as objects of both fundamental interest and technological relevance. So far, skyrmions were amply investigated in magnets, where due to the presence of chiral interactions, these topological objects were found to be intrinsically stabilized. Ferroelectrics on the other hand, lacking such chiral interactions, were somewhat left aside in this quest. Here we demonstrate, via the use of a first-principles-based framework, that skyrmionic configuration of polarization can be extrinsically stabilized in ferroelectric nanocomposites. The interplay between the considered confined geometry and the dipolar interaction underlying the ferroelectric phase instability induces skyrmionic configurations. The topological structure of the obtained electrical skyrmion can be mapped onto the topology of domain-wall junctions. Furthermore, the stabilized electrical skyrmion can be as small as a few nanometers, thus revealing prospective skyrmion-based applications of ferroelectric nanocomposites.
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50
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Young J, Stroppa A, Picozzi S, Rondinelli JM. Anharmonic lattice interactions in improper ferroelectrics for multiferroic design. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:283202. [PMID: 26125654 DOI: 10.1088/0953-8984/27/28/283202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The design and discovery of new multiferroics, or materials that display both ferroelectricity and long-range magnetic order, is of fundamental importance for new electronic technologies based on low-power consumption. Far too often, however, the mechanisms causing these properties to arise are incompatible or occur at ordering temperatures below room temperature. One design strategy which has gained considerable interest is to begin with a magnetic material, and find novel ways to induce a spontaneous electric polarization within the structure. To this end, anharmonic interactions coupling multiple lattice modes have been used to lift inversion symmetry in magnetic dielectrics. Here we provide an overview of the microscopic mechanisms by which various types of cooperative atomic displacements result in ferroelectricity through anharmonic multi-mode coupling, as well as the types of materials most conducive to these lattice instabilities. The review includes a description of the origins of the displacive modes, a classification of possible non-polar lattice modes, as well as how their coupling can produce spontaneous polarizations. We then survey the recent improper ferroelectric literature, and describe how the materials discussed fall within a proposed classification scheme, offering new directions for the theoretical design of magnetic ferroelectrics. Finally, we offer prospects for the future discovery of new magnetic improper ferroelectrics, as well as detail remaining challenges and open questions facing this exciting new field.
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Affiliation(s)
- Joshua Young
- Department of Materials Science and Engineering, Drexel University, Philadelphia, PA 19104, USA
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